viewed from a biological stand-point we find that they naturally divide themselves into two classes, viz., the contagious diseases, or those which are readily communicated; and the non-contagious or inoculable diseases, or those which are not readily communicated. If, in consonance with this idea, the same method of reasoning were carried further, it could also be shown that growths occurring in muscle and nerve, which are the most highly differentiated tissues in the body, possess no infectious or communicable property what ever; but we think that from this side of the question enough evidence has been brought forward to show that pulmonary tuberculosis both from its nature and relation is entirely devoid of contagion, and that it is no more communicable than cancer, syphilis, or any of the diseases with which it has the closest histological affinity. After having said this much on the deductive side of the non-contagious nature of pulmonary tuberculosis, we will endeavor to ascertain the trend of the evidence on its inductive side. This evidence divides itself naturally into that which has been gleaned from experiment, and into that which has been derived from clinical experience. The first consists in inoculating and feeding animals with, and compelling them to inhale, tuberculous material; and the second consists in tracing the influence which tuberculous patients exert on their living surroundings through ordinary intercourse. In regard to the experimental evidence, it may as a general rule be stated that artificial tuberculosis can be induced in the lower animals most readily by inoculation and least readily by feeding the poison, notwithstanding the facts that in numerous instances negative results are obtained by any method of introducing it; that many animals, like rabbits, guinea-pigs, etc., are more susceptible to its action than dogs, cats, etc.; and that it seems to be more communicable when introduced into the abdominal cavity than in the eyeball. The successful genesis of tubercle in this artificial way is, however, no more than one would be led to expect from a knowledge of its nature and of that of many kindred poisons, and is not the least evidence that they possess any contagious property; for abscess, gonorrhœa, malaria, etc., are communicated in the same manner, yet no one thinks of ascribing the power of contagion to these diseases. While, then, there is no doubt as to the inoculability of pulmonary tubercle, it remains to be proven whether this disease is ever trans mitted between man and man, or between man and animals through atmospheric contagion. For obvious reasons clinical evidence is the only umpire to which we can appeal for a solution of this part of the question, and in order to bring this clearly into view we shall endeavor to compare the salient characteristics of those diseases, which are undoubtedly contagious, with those of pulmonary tuberculosis. Exposure. As a rule those who are most exposed to a contagious disease are most liable to it, while the opposite is true of pulmonary tuberculosis. Do the practitioners of medicine, and especially those who believe in the contagiousness of the disease, take the proper precautions against infection in this manner, or do their actions fail to confirm their professions? On this point Professor Lichtheim expressed himself in no uncertain tones before the Second Medical Congress of Germany, which met in Wiesbaden in 1883. Among other things he said that it must be admitted that there are many facts which contradict the contagious nature of pulmonary phthisis. Intercourse with consumptive people is not attended with danger. We hospital physicians spend much time among such people, and we have such confidence in the innocuousness of the disease that we do not hesitate to mix healthy persons with them in institutions devoted to its treatment, and we must confess that this procedure is practically unattended by any unfavorable results. He further stated that the mortality of the attendants in the principal hospitals for consumption was surprisingly low; and that he could, from investigation, confirm the belief that there is no relation between the increase of the number of phthisical patients at a health resort and the number of deaths from consumption occurring among the native inhabi tants. The statistics of the Brompton Hospital for Consumption in London, as collected by Drs. Williams and Humphreys, speak in the same emphatic manner against the contagiousness of pulmonary tuberculosis. This large institution shows that during a period of thirty-six years not a single clearly authenticated case of pulmonary consumption among all its attachés emanated from within its walls. During the thirty-six years there were twentynine physicians and assistant physicians connected with the hospital, and among these occurred a single case of phthisis, and he was tuberculous before he entered it. The rest were all well. Dr. Edwards was resident for twenty-six years, yet he showed no sign of the disease. During that period there were employed one hundred and fifty clinical assistants. Of these eight died of consumption; but all, except one, were sufferers from the disease before they became connected with it, and in this one case there is doubt as to the origin of the trouble. Among the one hun Then, again, it is common to find physicians, both in this country and in Europe, who are sufferers from consumption, and therefore compelled to spend most of their lives in the mountain resorts of their native countries, to labor hard among their many fellow-sufferers who constantly crowd these places, and yet they experience no inconve dred and one nurses, of which there is a health ❘nience from their contact with these people, eight negative, and two hundred and sixtyone affirmative votes. Are we, therefore, justified in assuming that the two hundred and sixty-one opinions are of more weight than the seven hundred and seventy-eight negative ones, and thereby imply that the former only had the fortune or the misfortune to meet cases which originated through contagion, and that the latter had not? Is it not more probable that all of them witnessed cases around which hung a cloud of suspicion that they might be contagious, but that seven hundred and seventy-eight did not consider the proof strong enough to outweigh that which in their minds was in favor of other and more powerful influences in the production of the disease? Evidence of infection be- ❘ it cannot be denied that many young people that the histories of some of my cases are defective in information on this point, it is certain that the instances in which transmissibility may be suspected are not sufficient in number to be not allowed for as coincidences. It must, therefore, be concluded that the analysis of my cases does not furnish facts sufficient to render the communicability of phthisis probable." record, one is suffering from a slow form of the disease, which may have been contracted during her service at the hospital, although she is predisposed to consumption. She is an old employé, and able to attend to her duties efficiently most of her time. No more positive proof of the non-contagiousness of pulmonary phthisis could be gathered anywhere than is furnished by this large institution. Every one of the individuals associated with this hospital were almost constantly exposed to the disease, and still there is only a single case to which the least claim of contagion could be made, and this rests largely on suspicion. These statistics in regard to the non-contagiousness of phthisis are strikingly confirmed by those which relate to the influence of the Consumption Hospital of Görbersdorf, in Germany, on the death-rate from phthisis among the inhabitants of that town. Dr. Brehmer, who has been in charge of that institution for twenty years,* says that since the year 1854 more than ten thousand consumptives resided in the Görbersdorf hospital, who walked the streets of the town daily and commingled with its inhabitants. The latter were, therefore, constantly respiring an atmosphere more or less laden with tubercle-bacilli emanating from the dried expectorations of these consumptive visitors; yet, in spite of these favorable conditions for contagion, the mortality statistics of the town show that prior to 1854 there were 10.07 annual deaths from consumption among its inhabitants, while from 1854 to 1880 there were only 5.0 deaths per year, or a death-rate somewhat less than one-half of what it was before the introduction of the hospital. These figures are especially interesting in view of the assertions frequently made that the healthful influence of mountain resorts is impaired by the infectiousness of the exhalations and expectorations coming from consumptive people who go there for the purpose of seeking relief, showing that such suspicions are more imaginary than well founded. * Die Aetiologie der Chronischen Lungenschwindsucht, p. 18. but, on the other hand, regain exceptionally good health. Once more, not very long ago, Dr. J. SolisCohen, who has since become our honored President, said before this society that if any class of medical practitioners is more exposed to the virus of tubercle than another it is certainly the class to which he belongs, viz., the laryngologists. They are constantly operating on patients with tubercular ulceration of the throat, inhaling their breath and often their cough, and are continuously exposed to the evaporation of the sputum in the cuspadores of their offices, yet he was unaware of a solitary instance of infection brought about in this way. Contagion between Husband and Wife. In 1883 a committee, appointed by the British Medical Association, investigated the contagiousness of pulmonary phthisis by sending a printed circular asking the members of the profession throughout England whether they had observed any cases in which the disease was believed to have been communicated. The committee received ten hundred and seventy-eight answers. Of these, seven hundred and seventy-eight were negative, thirtynine were doubtful, and two hundred and sixty-one were affirmative. Of the affirmative answers, one hundred and fifty-eight were cases where the communication of the disease was supposed to have taken place between husband and wife, or vice versa, eighty-one between members of the same family, and the remainder were principally cases between whom there was no blood connection. On account of the large number of affirmative opinions, this report has been made to subserve the interests of those who believe in the contagiousness of phthisis. Evidently this is unfair, since the aim of the investigation was not to ascertain the number of absolutely well-demonstrated cases in which contagion was present or absent, for this would obviously have been next to an impossibility, but to collect the individual opinions of a large number of physicians as to whether they believed the disease contagious or not, and this resulted in seven hundred and seventy of these cases escaped even a suspicion of contagion, shows clearly that the disease is not by any means readily communicated under extraordinary circumstances. But is it beyond doubt that the thirty-two cases originated through contagion? We think not, for, as Dr. Schnyder says, it is a notorious fact that, in spite of all entreaties and warnings, young people are often wedded while suffering from active lung-disease. He relates four such cases in his own experience in which both the bride and bridegroom came to Weissenburg, fresh from the matrimonial altar, to be treated for phthisis, from which they both suffered. But even letting those who are wedded while suffering from active phthisis out of the question, tween married people is, we believe, much less common than it is generally believed to be. In our whole personal experience we can only recall a single instance where the wife may have contracted it in this way, although even in this case there is an incomplete family record, and the patient herself was a dressmaker and in all probability was predisposed to the disease. But were the fact of its communication established in any given case, it would still devolve upon the contagionists to prove that the virus was not introduced under very unusual conditions, such as being inoculated through an abrasion of the skin or mucous membrane by intimate contact of one person with another. As still further proof of the correctness of our view concerning the non-contagiousness of phthisis between husband and wife, we beg to call attention to a most admirable paper, entitled "Eine Statistische Studie als Beitrag zur Aetiologie der Lungenschwindsucht," contributed by Dr. Schnyder to Nos. 10, 11, and 12 of the Correspondenzblatt für Schweizer Aertzte for 1886. This contribution is based on three thousand four hundred and sixty-one cases of pulmonary phthisis, which were observed by its author while resident physician at the health resort of Weissenburg, in Germany. Of these cases, eight hundred and forty-four occurred among married people, but in four hundred and forty-five of them it was the husband only, and in three hundred and sixty-seven instances it was the wife only, while in thirty-two cases both husband and wife were affected. Now, it must be admitted by the most ardent contagionist that here existed the most favorable conditions for a propagation of the disease between husband and wife, or vice versa, through contagion; and the fact that eight hundred and twelve of both sexes carry the hereditary taint of the disease in their constitution, which only awakes from its slumbering condition to assert its power when the many varied burdens and demands of family life begin to exhaust the vital resources. Moreover, we have recently shown* that consumption makes its appearance in families which are perfectly free from all evidence of the disease. Proof based on two hundred cases of phthisis was there given, that the youngest members of families, provided either or both parents were the youngest members of their respective families, are especially predisposed to this disease. In view of this fact, it is of great importance to scrutinize the family record well before we jump at the conclusion that the disease must have been derived through contagion in the absence of a phthisical family history. On the point of communicability between husband and wife, the late Dr. Flint, in his work "On Phthisis" (p. 420), says, "In my collection of cases (670), these five are all that I find in which there is room for the suspicion of the disease having been communicated from the husband to the wife, or the wife to the husband. By making inquiries of members of the medical profession, and searching periodicals, doubtless a considerable number of similar cases might be obtained. Collected in this way, however, they would not prove communicability. According to the law of chances, a disease of such frequent occurrence as phthisis would affect in succession a husband and wife, or vice versa, in a certain proportion of cases. Conceding * "Some of the Causes of Pulmonary Consumption, viewed from a Darwinian Stand-point," Medical News, November 27, 1886. Baumgarten,* to whom belongs the credit of being a co-discoverer of the bacillus tuberculosis, and who implicitly believes that this organism is the causative agent of pulmonary phthisis, says that he never knew of a single well-established case of phthisis which was acquired through respiring an atmosphere vitiated by the exhalation of consumptive people. And he further says that during the last ten years he made and had made in the Pathological Institute at Königsberg a large number of inoculation experiments on rabbits with tuberculous material, constantly keeping inoculated animals in the same cage with the non-inoculated, the latter thus being exposed to an atmosphere infected with bacilli; yet in no single instance was the tubercular poison conveyed from the inoculated to the non-in Again, it is a well-known fact that phthisis may originate independently from a caseation centre located anywhere in the body outside of the lungs. Thus enlarged lymphatic glands of the neck, which so frequently follow dentition, or catarrhal affections of the mouth, may caseate at some inopportune time, and generate the specific virus which produces tubercle. Such glands are a standing menace to their possessor, and we have no doubt that ❘ oculated animal. they are the cause of at least some of the occult cases of tubercular phthisis. We have no doubt that pulmonary tuberculosis can arise from other infection centres in the body. Thus pyosalpinx, about which we have learned so much recently from Dr. Joseph Price, and from other members of this society, quite often goes on to caseation, and is said to be frequently accompanied, and probably followed, by tubercular involvement of the lung. How many such infection sources may originate spontaneously in the body as the legitimate product of ordinary catarrhal inflammation? Infectiousness of the tubercle-bacilli, or tuberclevirus, diffused throughout the atmosphere.-In the deductive or biological part of this paper we have given sufficient reason to show that one of the essential requirements in a contagious disease is the property of contaminating the surrounding atmosphere with an abundant crop of disease-germs. We also endeavored to give proof from this standpoint of the question that this is true of smallpox, and of all the active diseases of the external surface of the body, and that it is not true of sarcoma, tubercle, syphilis, or of any of the internal diseases of the body. We shall now inquire whether this harmonizes with the inductive or experimental evidence which can be collected on this point. Ever since it has been believed that the specific virus of tubercle resides in the bacilli, efforts have been repeatedly made to demonstrate the presence of these organisms in the atmosphere; and while it is claimed that they are always present, they have at no time been shown to exist in sufficient quantities to give rise to the danger of infection. Referring to the work of the two Italian experimenters, Celli and Guarnieri, who undertook to decide whether and under what circumstances a tuberculous person is liable to infect the surrounding atmosphere, Baumgarten describes the three series of experiments which these scientists made. In the first series they placed three ventilating devices, the inner surfaces of which were well covered with Koch's culture gelatin, at different elevations in the chamber of a consumptive patient. The air of the room was strained through these instruments for twelve nights in succession. Part of the gelatin at the end of this time was examined microscopically, and part was inoculated into the eye, the peritoneal cavity, and into the subcutaneous connective tissue of rabbits and of guinea-pigs. The second series consisted in allowing a number of phthisical patients to respire for a long time into a reservoir which was well coated with Koch's culture gelatin, after which the gelatin was examined microscopically and inoculated into the eye, peritoneal cavity, and subcutaneous connective tissue of rabbits and of guinea-pigs. In the third series they experimented with air which was aspirated through tubes containing tubercular sputum. The sputum was evaporated by heat, and the air thus exposed was forced through a tube containing sterilized blood-serum and Koch's gelatin. The experiments were continued for many hours, and in many instances were repeated. The culture media were then tested in the same manner as in the two former series,-viz., * Berliner Klinische Wochenschrift, 1884, p. 626. by microscopic examination and by inoculation. Every one of these experiments was followed by negative results. In no case did the microscope reveal a bacillus, nor was tuberculosis produced in any of the animals which were inoculated. Bollinger repeated the work of these two investigators on a vast scale, and confirmed their results in every particular. Tappeiner also imprisoned two rabbits in a closed cage, and allowed a tuberculous patient to cough into the cage. At the end of two months the animals were found to be free from all taint of tubercle. The results of these researches are all the more astonishing when the fact that in every instance the atmosphere was thoroughly exposed to the sources of tubercular contamination is taken in connection with the other fact that both rabbits and guinea-pigs are intensely susceptible to the tubercular poison. Surely the atmosphere here, if anywhere, must have contained tubercle-bacilli, and if not in number sufficient to produce infection, even when inoculated, how can infection possibly occur under ordinary atmospheric conditions? Unequal Distribution. -The non-contagious nature of pulmonary tuberculosis is also strikingly manifested when it is compared in point of distribution with well-known contagious diseases. The invasion of a disease like smallpox, for example, implies an epidemic, and a rapid exhaustion of the soil on which it thrives, after which it quickly declines. Its death-rate, no matter how large or how small, is never constant, but rises to a maximum one year and falls to a minimum the next, and then nearly or entirely disappears for a number of years, only to reappear and to re-exhaust the soil which has matured during its absence. But pulmonary tuberculosis never becomes epidemic, and has no soil to exhaust through contagion, unless it is the soil of human life. Its death-rate is so uniform from year to year that it becomes dolefully monotonous. During the last four years of which we have a record the number of deaths in the city of Philadelphia were nearly the same for each year, being 2809 in 1882, 2798 in 1883, 2801 in 1884, and 2821 in 1885; while, on the other hand, there were 1336 deaths from smallpox in 1881, and only 3 in 1885. It is thus seen that the course of a contagious disease is erratic, and that of pulmonary tuberculosis is so constant that a knowledge of its past enables us to foretell its mortality in the near future. Then, again, if pulmonary tuberculosis is contagious, why are we able to predict with a great degree of certainty that the badlynourished; those who are overworked, confined in-doors with sedentary employment; those who are overcrowded, or exposed to dampness; those who belong to a heterogeneous population; those who spend long terms in prisons; those who have weak circulatory organs; or those who are the youngest members of numerous families, are, if other things are equal, most prone to die of it? Has ever a contagious disease been more fastidious in the selection of its victims? Or, again, can contagion account for the fact, which Dr. Schnyder has so well shown in the article already quoted, that while in proportion to the male sex there are more females in German cities than in the country, yet 7.21 per cent. more females suffer from the disease in the country than in the city? Will any one be bold enough to pervert reason and say that the purer air of the country contains more bacilli or contagium germs than the city air? or will he, with Dr. Schnyder, believe that the greater liability of the females in the country is due to the fact that they are greatly more exposed to overwork and to all kinds of weather and temperature than their city sisters? Quarantine. If any further evidence were needed to prove that pulmonary tuberculosis is not spread by contagion, it could be found in the fact that the most rigorous quarantining and isolation of tuberculous patients has not the slightest influence in modifying the fatality of the disease, as is attested by the following history: In the year 1782* the authorities of the city of Naples decided that pulmonary tuberculosis was contagious, and logically enforced the most stringent preventive laws imaginable. Every practitioner of medicine was compelled to report every case of pulmonary phthisis immediately after discovery. Neglect of this duty exposed him to a fine of three hundred ducats, and the second offence was followed by imprisonment. Indigent patients were placed in a hospital at once. Their clothing and all their belongings were carefully isolated, and an accurate record kept of them. The punishment for non-compliance with this law was imprisonment. All furniture exposed to infection was ordered to be burned. After the patient's death or restoration his room was thoroughly renovated, * Uffelmann, Berlin. Klin. Wochenschrift, 1883, No. 24; cited after Brehmer. |