to expect, as Williams did actually show, that moment of the acme of its rise, or yet the profluoroscopy will reveal in the thorax also the fundity of its fall, but, rather, its rise and fall in physiologic undulations as concomitants of the statu actionis. The same is true of the pulmonary function of respiration? It is thus easy to stand-expansion; we can easily, in these days, make a ardize normal chest movements, to form a basis röntgenograph at full inspiration, full expiration upon which to judge abnormality. It has been or at any one point in the respiratory excursion, found, for example, that the normal excursion but how, in this way, can we watch the process of of the diaphragm, as judged by the movements of respiration, or compare the right and left chests its shadow on the fluorescent screen, is within in motion? certain constant limitations, depending, of course, (2) The diagnostic plate cannot offer another upon the force and extent of respiration, and dif- advantage which is presented by fluoroscopyfering slightly on the right and left sides. The that by which the operator is empowered to inexpansion of the lungs themselves may be care- crease or lessen, at his own pleasure, the penetratfully observed. As the lung becomes more and ing strength of the Röntgen rays at his command, more inflated, it becomes less resistant to the pas- in the course of a single exposure. In the microssage of x-rays, and this fact alone plays an im- copy of urinary sediments, we are familiar with portant part in one's power to recognize, not only the fact that certain delicate and diaphanous an area already diseased, but a tendency to dis-tube-casts are best observed when the light from ease through deficient expansion. It is just as the reflector is diminished or tempered. Can you easy to standardize the position and movements not conceive that the same necessity for holding of the heart in this way, as well as to discern any unusual appearance in connection with it, as is so often seen in pulmonary cases.

The remaining diagnostic agent of the Röntgen method is the photographic plate. What advantage has this, if any, over the screen, or does fluoroscopy, in its turn, have advantages not possessed by the plate? Williams said in 1901: "When instantaneous photography can be carried out in the lungs, a better opportunity will be offered for obtaining evidence of beginning pulmonary tuberculosis by the photograph than has hitherto been given." Our answer to this must be that we doubt that such time will ever come. Why? Because there is no such thing as instantaneous photography, and that there will be is the remotest sort of a possibility. Nevertheless, to the central idea of Doctor Williams's remark (to wit, that when we can obtain photographic results by exposures short enough to catch the lungs at rest, the plate method will become valuable), we are prepared definitely to answer. The routine exposure to x-rays necessary to obtain an impression of the adult thorax now is, or should be, sufficiently brief to be made easily while the patient holds his breath, either at inspiration, expiration or between the two.

It is partly on this account that examinations by röntgenography become valuable. They are valuable, also, from the fact that they furnish permanent records, to be examined at one's leisure, of existing abnormalities, and thus it becomes a simple matter to recognize a lesion which may have escaped the eye on the screen. The röntgenographic method furnishes, also, the possibility of making permanent records at various intervals in the progress of an individual's condition.

the penetrating power of the Röntgen rays in abeyance may arise when a delicate infiltration of an apex, for instance, is to be demonstrated?

--

(3) The diagnostic plate can show but one aspect of the patient any changes in position mean additional exposures. This is a difficult matter to overcome, as when the additional exposures are eventually made, many conditions, especially the degree of penetration of the x-rays, may have changed.

In order to look at the question with the greatest breadth of mind, we must consider certain qualifications of the röntgenograph not possessed by the screen:

(1) The screen cannot present its image permanently, and its images are of no value for purposes of record except as they form the bases for tracings, a matter later to be considered.

(2) The screen cannot so plainly convey its complete image on to the mind of the observer, although the deficiency may lie with the observer. no doubt. It is often hard for even a röntgenologist of experience to grasp, in the time usually occupied by a screen examination, all the points to be observed and noted. Subsequent examinations of the same shadow-complex are necessary, and Opportunity, in this as in other matters, knocks but once. On the other hand, the plate, produced at the time, forever repeats its story.

In the above disjointed manner, therefore, an attempt has been made to lay before you the pros and cons concerning the two great classifications of the Röntgen method of thoracic diagnosis. That these arguments for and against have many refinements and elaborations it seems hardly necessary to say. If one adheres too closely to the earlier method of fluoroscopy, he lays himself open to the criticism of being behind the times in Röntgen procedure; if, on the other hand, he be too quick to seize upon the röntgenographic method with its powers for brilliant results, he (1) The diagnostic plate cannot show moving may be charged with erratic desertion of the old structures. In attempting to make a diagnosis for the new. To all medical men who will give of pulmonary tuberculosis from the degree of the matter sober thought, it must appear evident respiratory embarrassment, the essential is, not that each method has so many good points that to observe the shadow of the diaphragm at the it cannot be shaken from its place by the other.

Many of my colleagues to the contrary notwithstanding, I am convinced that this method of examining a tuberculous chest cannot, to-day, supplant fluoroscopy for the following reasons:

The fluoroscopic method offers, to the trained less, we know that there does exist a prebacillary observer at least, a greater chance for mental bal-stage of the malady when to obtain the microancing and judgment. The röntgenographic organism is a most difficult matter. There are method, on the other hand, appeals more to the also instances, as has been mentioned, where it is clever technician as an opportunity to produce the brilliant results of his handiwork.

The fact is, gentlemen, we must accept both. We must accept the screen, because by that means we obtain a moving picture of living things obtainable in no other way. We must accept the plate also, just as, although we can feel the pulse at the radial artery, we are glad to accept a sphygmographic tracing of that pulse, or, although we can see the comet in the field of the telescope, we are glad to accept a detailed photograph of that comet and the surrounding solar system. Thus we find that the weapon we have received from Röntgen to use in this war on pulmonary tuberculosis is a double-edged sword. Although each edge cuts well, the weapon is most efficient when both are used.

no small task to elicit signs by the stethoscope. In the face of such facts as these, it would be absurd, indeed, to claim infallibility for the Röntgen method, or for any other. All methods are useful when chosen carefully, and it is only when one is carried to extremes that the others are lost sight of.

In well-marked or late cases, where signs and symptoms are all too clearly evident by any mode of diagnosis, Röntgen examinations are valuable, chiefly as confirmatory evidence, in direct proportion to the value of any other one method. They are also directly useful in determining the extent of well-established disease, and the character of suspected lesions, such as cavity or calcified tubercle. In this way it is not usually more useful than other methods.

It is necessary for us now to determine how While it is my desire to avoid mention of much of an addition this weapon is to our arma- technic as being outside the scope of this adment, formidable though it seems to be. In other dress, I wish merely to speak of one technical words, is the Röntgen method of diagnosis in pul- point. It is often desirable and advantageous to monary tuberculosis of value to us in the early obtain tracings or outlines of fluoroscopic appearcases? By early cases is here meant those cases ances as a means of rapid record or for teaching. which present no physical signs except, possibly, This can be done by following the shadows on the sight malaise with evening rise of temperature, a screen with a pencil or other marker on celluloid little loss of flesh, anemia and diminished appe- or some transparent substance, in front of the tite for food. It is in these cases that the most screen. It is essentially desirable that the traccarefully conducted procedures of auscultation and ing apparatus be so arranged that the source of percussion may offer little or no evidence. With- x-rays, which is behind the patient, may move out expectoration, it is most difficult to obtain the with each movement of the pencil, in any direcbacilli, and a Röntgen examination by means of tion. Thus it will be seen that the most direct the skiagraph offers no more satisfactory results x-rays will be always in a straight line from the than does the stethoscope. These are the cases pencil, and the element of distortion of shadow pre-eminently for fluoroscopy. What such cases will necessarily be reduced to a minimum. This present on the screen has been so well described is the principle of so-called orthodiagraphy, which by Williams and others who have given the matter unbiased judgment, that repetition is not necessary. Suffice it to say that this fluoroscopic evidence is often characterized by a lessened rise and fall of the diaphragm, and a diminished expansion of the thoracic walls, even if we do not perceive, What is to be the future of this science, as apwith the intensity of our x-rays under control, the plied to examinations of the chest? This is a unmistakable picture of a slight modification of the question which we may well hesitate to answer, usual brilliancy of the lung area at one apex. A for who, in 1896, could have imagined that a perlittle practice will enable one keenly to observe manent record of the thoracic contents on a these deficiencies, and even to measure the ab- photographic plate would eventually be made normality in centimeters. while the patient holds his breath? It is possible Such cases may present to the trained ear the to conceive that our most radical advances may suspicion, for example, of prolonged transpiration be exemplified by a combination of the röntgenoon one side, or to the sensitive finger the slightest graph and the cinematograph, or some other sense of resistance at one apex. This is undoubt-moving-picture device. Indeed, this has already edly true; but how often have cases been recorded been thought of seriously, and in a manner dewhere no such impressions have been conveyed scribed. Only render it practicable, and the day to the most skilled finger or acute ear, and in which will arrive when we may enjoy the altogether there has been found on the fluoroscopic screen novel sensation of gazing at the enlarged images of the pulmonary expansion and the diaphragmatic our pulsating hearts and our expanding lungs proexcursion very nearly, but not quite, as full upon jected through the stereopticon! As to the future one side as upon the other? none can say; the accomplishments of the past are marvels enough in themselves.

has been used, especially by the Germans, for some years. By thus outlining the application of tracings, I desire to correct the erroneous impression, created, possibly, by a previous remark, that no record can be obtained by fluoroscopy.

When a positive diagnosis in an early case is somewhat doubtful, one would never question the convincing proof established by the presence of the bacillus tuberculosis in the sputum; neverthe

Conclusions which may be drawn reasonably from these observations are:

(1) That the Röntgen rays, through the media

position, a previous infection, accidents which producing antibodies, for phagocytosis and the convert a latent or healing local into a general- other protective factors probably varies from ized disease, and finally the mode of entry. individual to individual, and has its definite,

As regards the virulence of the infecting prescribed limits. organism, I must admit that our methods are not The influence of one attack of tuberculosis, perfect enough to disclose minor differences. provided structures have not been seriously damUntil the facilities of the average laboratory ex-aged, must be considered a distinct asset, since we tend to the breeding and rearing of our experi- now know that immunization of cattle with mental animals, our tests upon animals can only human tubercle bacilli is possible. be relied upon to distinguish such gross differences in virulence as exist between the bovine and the human type. There are, however, differences between cultures of the human type which impress themselves upon the investigator as more or less constant, although it would be difficult to define them readily. We may safely assume that a considerable number of slightly varying races of human tubercle bacilli exists, and it is probably not a matter of indifference to the patient which of them is at work.

The influence of accidents, such as trauma, intercurrent diseases, secondary infections in favoring dissemination of the disease, is so well known that I merely mention them.

With all these factors at work and influencing the process, it is obvious that our inferences and conclusions as regards portals of entry, dissemination and the results of different kinds of treatment must be cautiously made, for they cannot safely rest on a few in part faulty experiments, which may strain and largely overpower the physiological protective mechanisms, and which may fail to reproduce the usual conditions present during spontaneous infection, but they must also take into consideration the work of pathological anatomy and histology, and utilize the results of statistics collected at the autopsy table.

Age is a most important factor, as all statistics and experimental inquiries show. In this respect tubercle bacilli do not differ materially from other infectious agents which find their easiest prey among the young. Statistics prove that tuberculosis becomes rapidly generalized in infancy and that it is a highly fatal disease. The conception Coming to the first controverted question, of latency which has been introduced into the whether all tuberculosis is chiefly or exclusively subject in recent years by von Behring does not alimentary in origin as maintained by some to-day. at all tally with such statistical and pathological we find that two different lines of research are researches. That a bacillus which is especially involved in it: virulent for the young should lie fallow in some

1. The anatomical and physiological problem

2. The behavior of the organism in the presence of tubercle bacilli in any of its tissues under the influence of different degrees of a specific resistance or immunity.

organ or tissue of the body without multiplying of the absorption of tubercle bacilli, soot, etc., by is, to say at least, revolutionary to our current the mucous membrane of the intestines and their conceptions. Experimenters have been for years conveyance to the lungs and thoracic lymph familiar with this conception of latency, or persist- nodes without being stopped by the mesenteric ence, of infectious agents in the body of those nodes. who are relatively immune, and of those who have recovered from a disease, but not with the idea that bacilli can be latent in the highly susceptible young. It is possible that such bacilli may be very feebly infectious, and that subsequent As regards the passage of bacilli through the disease is not due to them, but to later infection mucosa of the intestine it may be said that some with more virulent types. It is furthermore twenty years ago the opinion was quite general possible that certain antibodies may be trans- among pathologists that the tubercle bacillus mitted from mother to child, and that these are produces a lesion at the point of entry. With the slowly excreted and disappear after three or four more exact and detailed study of tuberculosis in months unless the mother's milk continues to infants and children, and the disease in cattle, supply them. Under such conditions it is con- this position had to be gradually abandoned. ceivable that, in the earliest months of life, or even To-day most authorities will admit that the longer, during the period of lactation, bacilli tubercle bacillus may pass through mucous memmay be restrained and then multiply subse- branes without leaving any pathological traces quently.1 In any case I doubt that such latency of its passage, to settle down in the nearest lymph could be prolonged over a year at the longest. nodes. The subject is a difficult one at best. How we can

How the bacilli gain an entrance into the tell in any case that there has been no fresh infec-lymph vessels of the mucosa, whether by the aid tion where we suppose the disease to have been of normal, physiological processes, or through latent, I do not see. The possibility of fresh minute lesions, is not determined. Their next infection with, perhaps, more virulent material station would be the mesenteric lymph nodes. must always be reckoned with.

The influence of inherited predisposition, though an unknown quantity, cannot be given up at present, and I believe it plays an important part in the fight with tuberculosis. The capacity for

In a former paper I advanced another hypothesis to explain

uch latency of tubercle bacilli: The Parasitism of the Tubercle

Bacillus, etc. Jour. Amer. Med. Asso., 1906.

The original claim held by many to-day is that in the mesenteric lymph nodes the tubercle bacilli come to rest and multiply, producing distinct lesions. If they escape it is only after leaving the well known traces of their passage behind.

Within the past four or five years a further modification of the original position has been

adopted by some, namely, that tubercle bacilli of both. If this pigment in these nodes comes may not only pass through mucous membranes, from the intestines, why does not some of it rebut also through the related lymph nodes and main in the mesenteric nodes? Why do these, settle down and produce disease at a point quite instead, retain in large numbers, chiefly in phagodistant from the point of entry, without leaving cytes, the blood pigment, and why is this not any intermediate traces of their passage. It is passed on? Possibly it may be answered that a obvious that if they escape through the mesenteric special chemotactic affinity exists between the lymph nodes their next stopping place would be phagocytes on the one hand, and the blood pigthe capillaries of the lungs and, as a result, we ment on the other, which does not exist between would have a primary tuberculosis of the lungs due phagocytes and soot, etc. But if this answer is to swallowing tubercle bacilli. That this is possible true, we surely cannot pass over the still more few pathologists will deny; but is it probable and important chemotactic affinity between tubercle is its occurrence of sufficient frequency and impor-bacilli and the cells of the mesenteric lymph nodes. tance to permit the overthrow of the aerogenic A careful reading of the recent literature infection in phthisis? Two lines of experiments shows that the promoters of the theory that have been made to prove this. Dogs have been tubercle bacilli may readily pass from the intesfed tubercle bacilli in milk or other fatty foods, tines to the lungs without stopping to multiply, and the tubercle bacilli found in the thoracic duct and thereby produce disturbances on the way, some hours later. Cattle have been fed with have not taken sufficiently into account the fact tubercle bacilli with stomach tube and slight that tubercle bacilli are not like grains of lamptuberculosis of the lungs produced. Animals black, but living organisms which arouse a more have been fed with various finely divided powders, or less prompt reaction on the part of the invading either with or without stomach tube, and the tissues, and which cannot travel about the body pigments found in the lungs. These various ex-at will without being recognized and held. periments, though plausible on the surface, do The varying conditions of immunity and prenot, in my mind, prove the contention. The disposition have much to do with the localization large number of bacilli introduced may have of tubercle bacilli and the shaping of the disease overpowered the usual protective agencies, there process. It is evident that the different stages may have been aspiration into the air tubes in life do not react alike towards tuberculosis. following withdrawal of the stomach tube, and finally other investigators claim that if pigments are fed in the usual way and kept wet they are not found in the lungs subsequently.

What may be true in earliest infancy is not absolutely so in childhood. Even puberty, middle life and old age have their respective types of tuberculosis from which, it is true, there are Perhaps the most opposition has been aroused deviations, owing to the variable factors already by the attempts to trace pulmonary anthracosis mentioned, but there is as a rule a clearly defined to the ingestion, rather than the inhalation of growing immunity with age. There is even a soot, a process firmly established by the exhaus-varying immunity of the different organs of the tive experiments of J. Arnold over twenty years same body towards the tubercle bacillus, and this ago. Without delaying over the experimental may not be the same at different ages. data, let me call attention to the fact that large The lungs may be said to be the locus minoris amounts of fine particles are taken into the diges- resistentiæ for tuberculosis, not only for man, but tive tract by our domestic animals daily in their for the higher mammals as well. Disease starting food, and if any absorption takes place it would elsewhere, if not checked by death or recovery, be detected. The mesenteric and meso-colic sooner or later leads up to the lungs. In my lymph nodes of the omnivorous dirt-eating pig second paper on bovine and human bacilli, pubare free from pigment. In the ox, the mesenteric lished nine years ago, this behavior of tubercle lymph nodes of the young are quite free from any bacilli was fully appreciated. It is there stated: pigment, but when the milk diet has been replaced" The question of phthisis as secondary to infecby the usual diet of grass, hay and grain, these tion by way of the digestive organs is, however, nodes become heavily pigmented, not with soot, one needing more attention. . . . In all mammals etc., but with pigment particles derived from the the lungs are evidently the most favored place of blood. When we turn to the thoracic lymph tubercle bacilli, and wherever the latter may be nodes in the same species draining the lungs, deposited, they sooner or later, unless the disease another picture presents itself. At first these is checked, reach those organs, where the process nodes are unpigmented, but as the animal grows older a faint subcortical line of pigment shows itself which grows heavier and denser with age. This consists of black particles and translucent fragments. In the horse similar conditions prevail. A delicate black tracery of the subpleural lymphatics in old animals indicates a frequent deposit in the lungs as well.

spreads more rapidly than elsewhere."

In the attempt to establish the alimentary origin of tuberculosis, some have based their arguments on the fact that inoculation into different parts of the body, even into the tail, may lead to the pulmonary disease. This fact has been known for a long time, and has been mentioned by various observers. The question before It is of interest, furthermore, to note that in us is not whether the lungs can be made diseased cows the primary foci of tuberculosis are situated secondarily. That this is possible, and occurs in the thoracic lymph nodes among the pigment, frequently, as in miliary tuberculosis, is well suggesting most convincingly the aerogenic source known. The real question is whether the usual