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In Wellesley College, where there were enrolled 1,593 students, the epidemic first appeared on September 18. Up to the middle of December they had had 280 cases. During six weeks of the epidemic 265 cases were reported and only one death occurred from broncho-pneumonia. For the most part, bright and sunny days were present, with only a few cloudy and rainy days. This college has not been without cases since September, but the epidemic lasted only about six weeks.

In a communication from Columbia University it is stated that the epidemic appeared during the week beginning September 22. No records were available for the student body at the time of inquiry, but in the Student Army Training Corps of 2,200 men between 8 and 9 per cent. had the disease during the period from October 1 to December 14. In this army group during this period two deaths from influenza and pneumonia occurred. The weather conditions in the city during this time were considered normal for fall weather--that is, mostly clear, with high winds. The opinion expressed was that the epidemic was still prevalent and increasing, and that a return wave seemed to be more virulent and affected the children of the city more than had the first one in the early fall.

There were enrolled at Harvard on October 1, 3,193 students. The first case of influenza occurred on September 20. There were 227 cases of influenza reported; of these there were 46 cases of broncho-pneumonia, with five deaths. There were two waves to the epidemic; the first wave height was in October and the second the last of November. The weather conditions were not severe nor particularly unfavorable at either time. The epidemic abated at the university largely because of the demobilization of the Student Army Training Corps. At that time it was still prevalent in Cambridge and Greater Boston.

At Yale University the disease first appeared in the New Haven Hospital on September 21. There were registered in all departments of the university 2,265 students. Up to the date of December 24, 1,013 cases have been treated. The number of deaths from broncho-pneumonia has been 249. At the height of the epidemic, which occurred in the third week of October, typical fall weather prevailed. An unusually clear, dry October with very little rain, much sunshine and rather low humidity was the weather report.

During the period of the epidemic at Princeton that university had 1,050 students, and the first cases appeared shortly after the opening of the college term on September 24. As a precautionary measure, every case, when even only suspicious, was sent to the infirmary. In all, there were about 70 cases in the university and about 45 cases from the United States School of Military Aeronautics. Only one member in the latter school died of pneumonia. There were no deaths among the students at the university. In this part of the country the weather was most delightful all autumn, being warm and dry, very little rain having occurred since the end of July. At the date of the inquiry the epidemic had disappeared--that is, about December 21--there being only two very mild cases under suspicion. In the town of Princeton, outside of the university, the conditions were much more serious than in the university itself. Influenza appeared in the homes of many of the poor people of the immigrant class, so that it was not uncommon for four or five members of one family to be infected at once. In one family of seven, five serious cases of pneumonia developed. An emergency hospital was opened by the authorities and 40 cases of pneumonia were treated. Of these approximately one-half died. At the time this report was furnished the epidemic seemed to have disappeared.

The number of students enrolled at the University of Virginia was 957. The first cases occurred as early as September 24. There were 290 of these in number, and three died of broncho-pneumonia. The epidemic was reported as having abated on December 15, but a few cases appeared after that date.

At the Army General Hospital No. 24, located at Hoboken, a few miles outside of the city of Pittsburgh, on September 28 two soldiers were taken ill and, with the disease unrecognized, they were removed to the cantonment hospital at Point Breeze, within the city proper. The men were found a few days later to be suffering from influenza, and from this presumable source an epidemic spread rapidly among the troops and student soldiers located here.

From September 28 until November 20, 1,392 cases of influenza occurred among the enlisted men. How the infection reached the first two cases at Hoboken is not known. The command here consisted of the Student Army Training Corps of the University of Pittsburgh, and Carnegie Institute of Technology, Motor Mechanics of the University of Pittsburgh and the Ordnance and Quartermasters' Department on detached service. The strength of this command was approximately 7,000. The first case appeared on September 30 and the diagnosis was made on the following day. Beginning October 13, all soldiers of this group were inoculated with two 1 cc. doses of vaccine, obtained from the New York State Board of Health. At the height of the epidemic there were about 840 soldier patients in the several hospitals of the city at one time. Cubicles were used in the hospitals, and in the barracks a floor space of 50 square feet was allowed to each man. The men slept alternately head to foot, with paper screens intervening, which were changed daily. In company formation they were instructed to gargle their throats and clean their teeth morning and night under the supervision of their officers. Strict military quarantine was maintained throughout the entire camp, no congregating was allowed, classes were suspended and only open-air drills were permitted. For the entire command there were 220 cases of pneumonia, with 99 deaths, an average mortality of 44 per cent. The dishes were boiled in the hospitals, and sanitary dishwashers were used in all mess halls. The kitchen help and personnel were inoculated with influenza vaccine, with apparently good results. The Magee Hospital, with 375 beds, was under strict military control. When this was full, all others were treated in the civilian hospitals.

In the city of Pittsburgh the disease was not made reportable until October 5. However, one case was reported on October 1, and it was known that there were a few isolated cases in Pittsburgh previous to that date. During the months of October, November and up to December 21 there were 23,268 cases of influenza reported, and the deaths were 1,374 from lobar pneumonia and 678 from broncho-pneumonia. We cannot but feel that most of the deaths reported during the period of the epidemic as lobar pneumonia were broncho-pneumonia associated with influenza. It was well known among civilians that true lobar pneumonia was exceedingly rare and has remained so up to the present time. This is especially noticeable, as this is the time of the year when lobar pneumonia is usually widespread in Western Pennsylvania. This district was particularly favored with a mild fall and winter. On October 1 the first case was reported, on October 15 the epidemic reached its peak--on that day 957 persons being reported ill with the disease. From October 16 until October 28 it maintained an average of 600 cases daily; from October 29 until October 31 there was a sharp decline from 600 cases daily down to 200 cases daily. From November 1 until December 21 the decline has been uniform, and on this latter date 58 cases of influenza and 7 of pneumonia were reported. The height of the epidemic was reached between October 15 and October 29. During the period of the epidemic in Pittsburgh, from October 1 until December 15, 62 days were recorded as cloudy, or partially cloudy, and only 14 days as clear, although the cloudy days seemed distributed and not in decided groups. The mean temperature for October was 58 degrees, with normal 54.9; for November, 44 degrees, normal 42.9; for December, 41 degrees, normal 34.7. The precipitation in October was 3.08, as against a normal of 2.36; in November, 1.79, with normal 2.55; and in December, 3.50, normal 2.73. From a study of these weather reports we see that the epidemic occurred during a period of abnormally warm, cloudy and slightly more moist autumnal season than usual, but these variations were relatively slight and far from decided. The confusion of diagnosis between lobar pneumonia and broncho-pneumonia, associated with or following influenza, occurred in the Pittsburgh health reports as well as in other cities. The presumption that almost all, if not all, of the cases reported as pneumonia of different types were really cases of influenzal pneumonia, seems justified.

During the time the epidemic was at its height in Pittsburgh the Western Pennsylvania Institution for the Blind was in session. This school is located in the heart of the educational center and was surrounded by the barracks of the Student Army Training Corps of the University of Pittsburgh and the Carnegie Institute of Technology. When the influenza was recognized as epidemic in this neighborhood, the attending physician at this institution advised a quarantine against the public. The children were refused visitors in the buildings, and the usual week-end trips home were forbidden. This school was continuously in session from September 24 until November 30. During this time there was not a single case of influenza in the school and the children were free from any infectious disease. On December 1 the pupils returned to school after the Thanksgiving holiday, and one week later, on December 8, the first case of influenza appeared. In a period of five days following 15 cases developed. It was considered wise to close the school, and all well children were sent to their homes. The institution was kept closed until January 1, since which time no cases have developed. Very few of these children had influenza at home, and only one death occurred.

A reliable report, subsequently confirmed by the health officer, stated that in Masontown, Pa., the start and course of the epidemic were very striking. A dance was held in the town and the musicians were brought from nearby cities. One of the musicians employed was not very well upon his arrival, and became so ill that after the dance he was put to bed in the hotel. He was found to be suffering from influenza when examined the following day, and from him as the primary case the town was swept by the epidemic.

In Mercer, Pa., the physician to the Board of Health reported that during September they had a general epidemic of coryza and sneezing, with slight fever, which lasted for three or four days. This was looked upon by the people as hay fever. In the midst of this, or about September 16, a man, 74 years of age, who had been away from home, developed true influenza, followed by pneumonia, from which he recovered about October 10. Another man, employed in Greenville, a nearby town, where influenza was already prevalent, returned to his family here suffering from the disease. The whole family and all who were exposed to this family were infected. From this family as a focus the disease spread rapidly in every direction. There were about 350 cases in the town of 2,000 inhabitants, and there were 9 deaths. Sporadic cases have occurred since, ranging in number from one to a dozen at a time. These numbers do not include scores of cases called colds by the people, but it seems that all these cases had an influenza element.

In the town of New Castle it was not possible to trace the onset of the influenza epidemic to a definite case. As the health officer stated, several cases were reported at once.

The first case of influenza in Indiana, Pa., of which there was any definite knowledge occurred on September 15. A clothing merchant who had just arrived from New York, where he had been buying stock for his store, was the first case identified. The next case occurred several weeks later, the disease being contracted at the mining town of Coal Run, in Indiana County.

Reviewing the history of former epidemics and pandemics, I have gained the impression, as have many others, that we are not dealing with any new disease. Further, our knowledge of this pandemic with its high incidence of broncho-pneumonia shows that it is in no way markedly different from that of former manifestations of influenza. One is impressed by the fact that in different outbreaks of this disease of complex symptomatology certain symptoms or complications have been prominent, overshadowing others, and making such complications the striking feature at the time. The failure to recognize that these varying features are merely different manifestations of one disease has resulted in much confusion. The observation made in the last epidemic--and one which can be endorsed during the present plague--is that influenza has been and is the most widespread, rapid and extensive of all diseases. One thing also that attracts attention at the present time is the long period existing between the several pandemics. Whether, as one observer during the present pandemic has stated, it requires a long period for the infection to become active and easily carried, or whether any possible reason can be suggested for these phenomena, admits of no satisfactory explanation. The outstanding feature during this epidemic is the complication of broncho-pneumonia, and yet, from very early times, this complication has been repeatedly spoken of as a striking characteristic. Reviewing the health reports from the large cities of deaths from pneumonia, the presumptive opinion seems justified that almost all, if not all, pneumonias reported as associated with influenza were of the broncho-pneumonia type. The infrequent presence, indeed the rare finding, of lobar pneumonia during this period in Pittsburgh seems to verify the aforesaid opinion. The great frequency and the high mortality of broncho-pneumonia were particularly noted during the present epidemic. During the present epidemic the great mortality among pregnant women was another striking feature, and yet this is by no means new, having been recorded by some of the earliest writers. Such also may be said of the recurrence of the disease in the same patient. One important observation brought out in the study of the pandemic of 1889 to 1892 was that the ordinary infections occurring in the spring and fall known as grippe or La Grippe are in no way connected with the pandemics which have occurred. There seems to be a consensus of opinions among the records of the more recent epidemics, as well as during the present pandemic, that weather conditions in no way influence the spread of the disease. Furthermore, a study of weather conditions throughout the United States, and particularly those of our own city, seem to bear out the truth of this observation. While clinicians during other epidemics expressed their belief in the incident of a primary case producing infection, it has only been during the present one that such an opinion has not been assailed. The large number of military training camps and cantonments have undoubtedly offered splendid opportunity for the spread of influenza. The futility of attempting to control it even under normal conditions is still questionable. Consistent with former reported invasions of the disease, the present epidemic lasted a definite period. This period was about six weeks in most of our large cities, colleges and institutions, extending approximately from October 1 to November 15.

It is imperative to note the accurate clinical observations recorded from the numerous epidemics of the past by men with far less data to go upon than is available at the present day. The high morbidity among the personnel of many of our hospitals and institutions where the infection occurred and the relatively low mortality deserve attention. This may be partly explained by the methods of treatment of those infected, but not entirely. The great likelihood of carriers of influenza, who either are not ill or who are suffering from very mild infection, is an observation also noted by former writers which cannot be ignored. The value of the masks has not been established, although they have been extensively used in many parts of the country. Frequent throat lavage was generally accepted as a rational preventive measure. Relightings of the disease have been noted in most of our cities after the subsidence of the epidemic. Vaccination against influenza is fully discussed in Dr. Haythorn's paper in this series.

The presence of influenza in San Quentin prison, California, in April, 1918 ; an epidemic of respiratory disease in Chicago in the spring of 1918; the report of Soper of influenza in our army camps in March and April, 1918; the occurrence of influenza in Porto Rico in June; influenza on a United States Army transport from San Francisco, as reported by Coutant, seem to point to the possibility that influenza had a footing in America long before the disease became pandemic. The view held by some that the beginning of influenza was in America, subsequently being transferred to Europe and then reimported here, is worthy of consideration. Coutant believed the disease originated in Manila, others that it traveled from "a permanent endemic focus in Turkestan," and there are many other theories which attempt to discover the original source of the disease. The question is today an unsettled one. The pandemic of influenza in its severest form swept so suddenly over the world that before the profession realized it or had become stabilized it had changed its character and the great plague was gone. The consequence has been that we have really learned little that is new and have done scarcely more than establish on a firm basis many of the opinions formed after the great outbreak of some 30 years ago. Because transportation is today more rapid than it was at that time, so the spread of the disease has been correspondingly swift. Our modern life, the congregating crowds in theatres, moving-picture houses and in lecture halls, as well as of the men in our training camps, the development of street cars and the more frequent traveling by train--these and many more changes in our mode of living have served to aggravate the conditions favoring the widespread distribution of the infecting agent. A higher proportion of the population was, therefore, attacked than in any previous pandemic, and the period during which the disease was widely prevalent has for the same reason been relatively much shorter.

The characters differed somewhat in different regions, but the evidence shows clearly that we are not dealing with any new disease. It will be years before we are able to fully analyze the data that have been collected from such wide sources and by so large a body of trained men, so that important epidemiological facts may still be forthcoming from the material already at hand. We are too close to the events to get the most helpful perspective, and the object of this report has been to add, in however small a degree, to the general knowledge of this great pandemic as it has appeared to us in Pittsburgh and its surroundings.

A CLINICAL DESCRIPTION OF INFLUENZA AS IT APPEARED IN THE EPIDEMIC OF 1918-1919

The epidemics of influenza which have been recorded from time to time during the past few centuries have always contributed an interesting chapter to the history of medicine. The protean character of the disease with its many complications is always an excuse for another attempt at the description of the clinical manifestations of a recent epidemic. This is not, however, the only incentive at the present time for describing the clinical aspect of the disease as it appeared in the epidemic through which we have just passed. The study of the disease from other aspects, such as the pathological, the bacteriological and the physiological, by well-organized groups of workers has made it necessary to co-ordinate, if possible, the clinical findings in every detail with these apparently basic principles. It would be interesting to review here the peculiarly fortunate circumstances which have led to the investigations. On account of the great war many temporary laboratory organizations which otherwise would not have existed were in operation, and these organizations, moreover, were keen to undertake any laboratory problem which might arise. The present epidemic presented the opportunity, and that the work was taken up with great enthusiasm is evidenced by the reports coming from the various army hospitals, base hospitals and civilian hospitals throughout the world. The permanent laboratories connected with medical schools and with institutions for medical research took up the problems with equal endeavor. This brief reference is made only to call attention to the fact that from such organizations a great mass of information has come which must be critically reviewed and coordinated before it can add to the permanent fund of our knowledge of the disease under consideration.

The material upon which the following clinical observations have been made is peculiarly adapted to review because it consists of two distinct groups of patients which were admitted to the Mercy Hospital. One group of 153 men was composed of soldiers between the ages of 18 and 23, which had been recently inducted into the Student Army Training Corps, and were living in barracks in the immediate vicinity of the hospital. Another group consisted of civilians , ranging from youth to old age, which came from various parts of the city and surrounding towns and country. The first group came to the hospital early, or as soon as the disease was recognized; the second group came usually after several days of illness had elapsed, or when a complication had already arisen. Many of this group had been ambulatory cases for the first part of the disease. The entire number of patients admitted to the Mercy Hospital from the first admission, September 21 to December 1, the end of the quarantine, was 547. After December 1 very few simple influenza cases were admitted. These 547 cases form the basis of the observations which will be referred to in this paper.

From the last great epidemic or pandemic of influenza, that of 1889 and 1890, have come clinical descriptions which should be reviewed before speaking of the clinical manifestations which have characterized the present epidemic as shown in the two groups studied.

One of the best descriptions of that epidemic was given by Dr. O. Leichtenstern in Nothnagel's Encyclopedia of Practical Medicine. This contribution, among many others, describing the epidemic of 1889 and 1890 is one of the first to refer to the Pfeiffer bacillus as being etiologically associated with the disease. It differs, therefore, greatly from descriptions of previous epidemics. Leichtenstern says: "The typical influenza consists of a sudden pyrexia of from one to several days duration, commencing with a rigor, and accompanied by severe headache, generally frontal, with the pains in the back and limbs, by prostration quite out of proportion to other symptoms and marked loss of appetite." He continues by saying that to these characteristic symptoms may be added the catarrhal phenomena arising from the affection of the respiratory tract, particularly the upper and "occasionally" the lower, the trachea and bronchi. This description is so in accord with the symptoms of uncomplicated influenza as found in the present epidemic that very little need be added. Any difference which may occur in the description of the disease is likely to be accounted for by the peculiarity of onset, whether in the upper or lower respiratory tract, and by the different ways of interpreting complications which may have arisen. It is evident from this description that the upper respiratory tract was affected more generally than the lower in the epidemic of 1889 and 1890. In the present epidemic it can safely be said that the reverse was the usual state of affairs. It was a rather unusual occurrence when the affection was limited only to the nose, pharynx, larynx, trachea and larger bronchi. A very large number, no doubt, had a peculiar oedema, a so-called "wet lung," which we shall discuss later; others went on to a capillary bronchitis or a bronchiolitis, and a large number had broncho-pneumonia. This sequence we shall attempt to show in the statistics at hand. In some cases the lesion in the lower respiratory tract seemed to be primary, there having been no initial coryza. At least none was observed and no history was obtained.

The length of the prodromal stage--the stage from the time of contact to the earliest onset of symptoms--has always led to interesting observations and discussion. In this epidemic we have rather definite information bearing upon this subject.

A young married farmer living in a rural community where no influenza had occurred up to the time of the present experience went to a city about 40 miles distant. On the train he sat in the same seat with a man who was apparently ill, and who was sneezing and coughing. He was in the city only a few hours, and was not in any place of congregation except the railway train. Forty-eight hours after his return to his home he noticed the first symptoms and began a mild course of influenza. About 50 hours later his wife was taken with the same symptoms, and in two days more their only child was afflicted. Other members of the household were also afflicted, and one of them died of pneumonia.

It might be interesting to quote a similar observation made by Macdonald and Lyth, of York, England, published in a recent issue of the British Medical Journal , which corroborates this experience. They say: "We traveled from London together on Thursday, October 3, by train, leaving King's Cross at 5.30 P. M., arriving in York at 9.30, and as we were leaving the carriage a young flying officer, who had come the whole way with us and was coughing and sneezing at intervals, informed us that he was ill and had had influenza for several days. On Saturday, October 5, we both became ill and had developed typical attacks of influenza. With both of us the illness developed suddenly with laryngitis; in both the first signs were a severe attack of coughing; and in both the time was noted fairly accurately as being between 2 and 2.30 P. M. One case was quite mild, the temperature never over 101. The other was more severe; the temperature arose to 104 1/2 and the catarrh extended to the bronchi. His wife and two children also developed influenza, and in their case the symptoms showed suddenly, about 2 P. M., on Monday, October 7. Now we are convinced that we became infected from our traveling companion during the train journey--more likely toward the end of the journey; and if we take the time of infection as 9.30, this fixes the incubation period for both of us at a minimum of 41 hours, with a maximum margin of error of 4 hours. The three cases developing in the family of one of us point to a similar incubation period, as their illness started almost exactly 48 hours after his, and as it is likely that the infection would not take place until a few hours after the first symptom, the incubation period in these three cases must have been nearly the same as our own two.

"It can be readily understood that we were in no position to conduct extensive bacteriological examinations, but a culture taken from the posterior nares of one of us on October 10 with a guarded swab showed colonies of Pfeiffer's bacillus and of micrococcus catarrhalis."

This observation is so convincing, I have quoted it at length and in full.

The communicability of influenza has been observed by all, and the ease with which it passes from one individual to another noted. One observation made by us was of considerable interest. In a house where a patient lay sick with a severe attack of influenza for nearly three weeks several members of the household passed the door of the sick room a number of times daily, and yet they did not contract the disease. This is in marked contrast with the immediate contact between the two physicians and the young flying officer, who sat in the same railway carriage compartment for four hours. The same observation was made in the hospital among nurses in direct contact with patients. A large number of these contracted the disease, while those not immediately associated with influenza patients almost invariably escaped. This speaks strongly against the idea that the epidemic was a so-called "plague," or that it passed without intermediate means through the air and pervaded all places.

From information thus far at hand it seems, therefore, that the prodromal stage, or stage of incubation, is one which covers about 48 hours, and that it is usually without symptoms unless it be a peculiar prostration which had been described by some patients. It would also appear from the experiences just narrated that it was necessary to be in rather close contact with a patient, so that there could be an exchange of respired air before infection could take place.

In all descriptions of the disease the duration is spoken of as "several days, more or less," "a three-day fever," or "a seven-day fever." Because of the careful supervision under which the soldiers were kept while in the barracks an excellent opportunity was afforded to note the duration of uncomplicated cases. The shortest time observed was 1 day, and the longest 10 days. The average duration of temperature among 87 soldiers without inflammation of the lungs or other certain complications was 6 1/3 days. Among the civilians the shortest time of pyrexia was a few hours only, while the longest in 73 male patients was 14 days, and in 84 female patients was 16 days. The average length of pyrexia in the males was 4 5/8 days, and in the females was 5 1/4 days.

While the very definite clinical description of the former epidemics of a so-called uncomplicated influenza seems to have served satisfactorily to the present time, the laboratory studies and the possibly more thorough clinical observations which have been carried out recently in this epidemic make it necessary to present anew the whole disease picture of influenza, with the hope of suggesting a classification more in accord with our present knowledge of the disease.

A few words as to "forms" or varieties of influenza might be helpful before suggesting a classification of symptoms. In former epidemics of influenza considerable importance was attached to the early manifestations or first symptoms as characterizing the "form" of influenza which was in evidence in the individual patient. These were reported as a "respiratory form," a "nervous form," a "gastro-intestinal form," and other forms--circulatory, renal, psychic, etc. In the epidemic of 1889 and 1890 particularly these types were noted, and they have been described in the subsequent small epidemics, practically characterizing them as being of one or the other, and frequently as being without any respiratory symptoms. In the study of our group of cases in the present epidemic every effort was made to recognize the non-respiratory cases, but we were unable to find a single case which did not have definite respiratory symptoms, either early or late, in addition to any other symptoms present. Only occasionally were nausea, vomiting and diarrhea or tachycardia, or certain neuroses or psychoses, the leading symptoms. The respiratory symptoms in some cases seemed to be at the onset primarily of the lower respiratory system--that is, without the preliminary coryza. These usually ran a rapidly fatal course, characterized by marked cyanosis and confusingly irregular chest signs. We would say, therefore, in so far as our experience goes in this epidemic, we are not justified in speaking of any particular forms except the respiratory form, and whenever pronounced manifestations occurred justifying a characterization of any other form they could more easily be interpreted as a complication, or the manifestation of a coincident disease, or of a severe toxaemia.

The classification of the symptoms, therefore, takes into consideration largely those symptoms arising from the respiratory system. We are of the impression that the pathology demonstrated by Dr. Klotz and described by others justifies the following classification. Clinically we would recognize two distinct groups of epidemic cases.

Of the group without lung involvement nothing further would seem necessary to be said in addition to what one finds in standard text-books describing the disease picture of former epidemics. The incidence of influenza of this type among our group was as follows: Of 153 soldiers 93, or about 60 per cent., had a so-called simple, uncomplicated influenza, and of the 394 civilians 185, or about 52 per cent., had no lung involvement. There are a few points in which the symptoms of the present epidemic seem to be so peculiar that they merit special consideration.

This can be described as showing a sudden rise to 102-104, at which point it is maintained for a few days, and subsides by lysis in a few days more. A typical chart is as follows:

This would occur without our being able to find any lung lesion unless we accept the acute oedema or wet lung as a complication, and this we were rarely able to recognize by any definite physical signs in the chest. Cyanosis frequently accompanied this second rise of temperature, and was later interpreted as being associated with the so-called wet lung. When the temperature remained up longer than five days it could safely be concluded that lung involvement must be present.

The pulse was invariably slow, or rather out of proportion to the temperature. Even when the patient seemed very ill the pulse remained from 84 to 96, and of surprisingly good quality. This was noted also when some of the more severe pulmonary involvements or some complications arose. The pulse frequently did not become rapid until shortly before death. The respirations in an uncomplicated case also remained about normal. The rate was not accelerated until lung complications arose, and then a gradually increasing rate was often the first herald of oncoming danger and a sign of grave prognostic import. The relation of the pulse phenomena toward the end of a fatal case was most remarkable. The respiratory rate was accelerated, as has been noted above, but the pulse rate frequently remained unchanged, being characteristically slow. In a patient seen in consultation with Dr. Lester H. Botkin, of Duquesne, Pa., death took place while we were in the sick room. It was a case of apparently uncomplicated influenza of seven days' duration. The respirations were rapid and the pulse was only 96. In the last five minutes of life the heart beats as observed with the stethoscope never varied, until they suddenly ceased; during the same time the respiratory efforts were only three agonal ones, the last being a minute or so before the last heart beat. There were no physical signs of consolidation at any time recognized in this case, but we feel that the lung, had we seen it at autopsy, would in all likelihood have shown the peculiar hemorrhagic and oedematous character so often observed in the fatal cases.

There were, of course, marked exceptions to the description of slow pulse and later rapid respirations observed. In some the pulse rate and respirations increased, together with or without definite signs of a grave complication.

The blood pressure in those cases in which cyanosis was observed was invariably low. This seemed to be due to the infection, for in several private patients not belonging to this group of patients with previously known high blood pressures the blood pressure was observed as much lower throughout the course of the infection.

The peculiar behavior of the white blood corpuscles will be discussed more fully in another paper of this series. Our remarks will deal more particularly with the clinical observations and interpretations. The leucocytes fell below the normal from the very onset of the disease; they varied very little regardless of great changes in temperature; they did not always increase, or if they did increase at all it was comparatively little, even in an extensive invasion of the lungs or in severe complications. Concerning the leucopenia we have no explanation to suggest, save that it is a clinical characteristic of the disease. Our first thought was that the infection came on so suddenly and profoundly there was no time for a leucocyte reaction. But when we recall other diseases associated with a leucopenia, notably typhoid fever, which does not come on with such suddenness, our explanation for the leucopenia of influenza does not seem to hold. The leucopenia must be simply a peculiar toxic blood reaction characteristic of the Pfeiffer bacillus invasion. Such an explanation has long been accepted in the Eberth bacillus infection.

A condition which was frequently noted by the patient was an indescribable weakness and prostration which appeared early, sometimes before any other symptoms were noted or before any elevation of temperature. The young soldier was in apparent perfect condition when he arose in the early morning. During the "setting up" exercises he did not feel so fit, and a few hours later appeared extremely weak. When his condition was called to the attention of the medical officers he was found to have a slight elevation of temperature and was sent to his bed.

In former epidemics, as also in this one, marked prostration was recognized as coming at the height of the disease and remaining persistently during convalescence. But it does not seem to be recorded as among the first symptoms.

Of the group with lung involvement much may be written from a clinical standpoint, and much confusion may be brought about. Especially is this so if one has no definite idea of the pathology present, or if one enters into a discussion of the character of the infection--a point upon which there is as yet no unanimity of opinion. From the many reports which have been put forth from the base hospitals of the various cantonments, and also from the reports coming from civilian practice, it is evident that scarcely any two groups of laboratory men or any two individuals of those separate groups have the same idea as to the bacteriology and the pathology peculiar to this epidemic.

As long as there is this confusion and element of doubt in the minds of those to whom we are accustomed to look, the clinician must necessarily speak with considerable hesitancy, especially when he attempts to interpret the physical signs observed. In our own group the observations of Klotz, Guthrie, Holman and others have given us an interpretation of our clinical findings which, at present at least, is more or less satisfactory. We shall definitely keep in mind their observations and conclusions as we go on with the description of the physical signs of the chest in cases having lung involvement.

In the description of this group it will readily be seen that the lower respiratory tract stood the brunt of the infection. Of the 153 soldiers under our care, 60, or about 40 per cent., were recognized as having pneumonia. Of these, 34 had undoubted demonstrable signs, while 26 were questionable, and yet from the temperature and other symptoms we concluded there was a pneumonia. Of the 394 civilians, 189, or about 50 per cent., had pneumonia. Of this group there were again some 28 or 30 in which the diagnosis was doubtful, according to the ordinary way of making a diagnosis, but we felt sure from the temperature course that more than a simple influenza was present. In the description of the physical findings of the chest in these influenzas with lung involvement it will be readily seen why the diagnosis must sometimes be in doubt.

Before referring to the physical signs it might be well to describe the condition and general appearance of the patient when the lungs became involved. The patient who had been progressing with an apparently simple influenza, with no chest signs except those of bronchitis or tracheitis, occasionally slightly cyanotic, became more cyanotic, the elevation of temperature continued longer than three to seven days, or if it came to the normal began to rise again, his respirations gradually increased and the pain in the chest became well localized. One could safely assume that the patient had developed a lesion in the chest. This could not always be localized during the first few hours or on the first day. The evidence of increased bronchial disturbance was frequently recognized, and later impairment of resonance and diminished breath sounds associated with "a few crackles" were noted. This, so far as we can tell, may have been the only evidence of the stage of oedema or "wet lung." After this, as the disease advanced, definitely increased vocal fremitus and rather definite tubular breathing with greater impairment of resonance were noticed. These signs were usually observed first at the apex of the left lower lobe, and from here they extended forward along the inter-lobar sulcus, or downward along the spinal column. If the lesion was noticed first on the left side, in a day or two it was found more or less definitely in the right lower lobe also. It seemed to occur more frequently first in the body of the right lobe, instead of in the apex of the lobe as on the left side. In both lobes it might spread to contiguous areas and form a massive consolidation, or it might be found in small separate areas, some of which would clear up in a day, while others would persist.

The expectoration was frothy, containing either blood or masses of yellowish, greenish purulent material floating in a watery sanguiolent or clear fluid, or enmeshed in frothy mucus. The amount of expectoration in some cases was enormous, but as a rule it was scanty. It was thick and ropy at times and distinctly annoying to the patient.

At this stage the physical signs were very much in accord with those of broncho-pneumonia. In a few hours sometimes, or in a day, the small areas of consolidation became confluent and massive consolidation was formed. It appeared as though the whole lobe would in time become solid, as in a true lobar pneumonia. Or the original areas may apparently have cleared and other areas involved, became the centers of massive consolidations. In many cases both lower lobes were thus similarly affected, and one had the physical signs of a double lobar pneumonia. However, nearly always a small angle of the lobe remained clear, thus differing from the entire lobe involvement characteristic of a true croupous pneumonia. Other signs, such as the absence of vesicular breathing and presence of the crepitant r?le, moist r?les of all sizes to very coarse r?les, could be noted. As in certain stages of a complete consolidation, the lung might be dry; no r?les present, but definite tubular breathing present. This in a day or two, or after a longer time, might give the signs of resolution. The stage of resolution, however, was almost invariably prolonged, sometimes extending over weeks. With these variable lung signs were often mingled the signs of a fibrinous or serofibrinous pleurisy, which occasionally but remarkably infrequently went on to effusion or empyaema.

As stated above, the demonstrable pathology was in the lower lobe, and more frequently in the left than in the right, only occasionally in the middle lobe, and never, we might say, in the upper lobes. The very earliest definite signs were found at the apex of the left lower lobe.

This observation seems to be entirely contradictory to that of the pathologist, who found in 65 per cent. of all cases coming to autopsy a lesion in all the lobes of the lungs . The only explanation we can give which seems at all satisfactory to us is that the pathology in the upper and middle lobes must not have been sufficient, or must have been of such a nature that it did not yield the physical signs, i. e., definite impaired percussion resonance, increased vocal fremitus and tubular breathing, with varying shades of moist r?les--signs upon which we insisted before we were willing to state definitely that there is a demonstrable pneumonia present.

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