kind are already in operation there. Plans have been made and carried out in Sweden for protecting the working people against contracting the disease, as well as protecting the children of the tuberculous from becoming infected. Social hygienic experiments were made in the parish of Lower Lulea, in Sweden, for improving the condition of things in known tuberculous areas. In short, no phase of the problem has been overlooked in that progressive country.

Other countries, France, Switzerland, Austro-Hungary, Brazil, Cuba, etc., showed what they are doing in working out the salvation of their people. The movement is going on swiftly, and results of decided worth are already recorded. This the exhibition halls of the Congress showed in unmistakable manner.

The initial meeting of the general Congress was held on September 28, 1908. It was presided over by the Secretary of the United States Treasury, acting for the President, Mr. Roosevelt. Each country was represented by an official delegate, thirty-three in all, Japan alone of all the civilized nations being conspicuous by having no representation. The official representatives, in short addresses, voiced the sentiments of their respective countries, and assured the Congress of their good wishes and desire to co-operate effectively in stamping out tuberculosis. The gathering was a remarkable one, and the general impression prevailed after the meeting that such united action certainly indicated that very effective work would be accomplished. Tremendous enthusiasm prevailed when Robert Koch, presenting the compliments of his country, the Imperial German Empire, arose and assured the Congress that the work in Germany is being seriously undertaken, and that the Robert Koch Stiftung, or grant, was created for the sole purpose of solving this problem. The general sessions and the section meetings were given over completely to the discussion of the scientific research work on tuberculosis, the means of early diagnosis, and the methods of cure, as well as to the recognition of the alarming prevalence of the disease, and the best means to be taken to protect the healthy from fresh infection. The theme of the meeting was the education of the public. The exhibits attempted to educate the public, as well as the profession. The formal papers were devoted to a consideration of the means of educating the medical profession on its duties. towards the tuberculous-infected people of the world, in teaching them how to get well and stay well, as well as in educating them to protect their uninoculated neighbors.

The greatest factor in prevention and curing tuberculosis is the following-out of some simple rules of living-sunshine and fresh air, the eating of good food, and the avoidance of excesses. There was an inscription written upon the wall of the exhibit of the University of Wisconsin, which was quoted from the writings of Gabriel d'Annunzio, the great Italian novelist. It was as follows: "Come with me, out into the

sunshine." This quotation practically expressed the modern conception. of the proper treatment of early tuberculosis. It was portrayed and the sense carried out in practically every exhibit, and in every paper read before the Congress. The essence of tuberculosis treatment is fresh air and sunshine. The whole civilized world now appreciates the fact that tuberculosis is a curable disease, that it is curable by following out the ordinary rules of personal hygiene, that its recognition should and can be early made, that so-called "climatic" treatment is a thing of the past. The wildest enthusiasts on the "climatic" treatment of tuberculosis acknowledged, at this Congress, that a patient in the beginning stages of tuberculosis can be cured as easily in Missouri, or Kansas, or New York, or Vermont, or Louisiana, or Minnesota, as he can in Colorado, or Southern California, or New Mexico. It is not necessarily so much a question of putting a patient into a supposedly favorable climate as it is to get him to live in the open air, to sleep in the open air, to live correctly, to eat properly, and to avoid alcoholic and other excesses, at the same time to do a certain amount of physical labor, not beyond his individual capacity. There was unmistakable condemnation of the practice that has prevailed so long of physicians assuring patients, in any or all stages of the disease, to seek other climes, irrespective of physical conditions, irrespective of the financial status of the patient, and regardless of the danger of nostalgia attacking a stranger in a strange land. Nostalgia is the great foe to the tuberculous patient who seeks a climate that has been pointed out to him by medical and lay friends as a veritable El Dorado of health. Nostalgia has sent many a tuberculous person back to his "home" climate from a "favorable" climate, in a coffin. Possibly the greatest mistake that the medical profession has made in the past is the common practice of believing that a patient can get well in Colorado, New Mexico, Texas or California, if he can only get there; and greater still is the mistake that many doctors are making of telling these patients not to seek medical advice when they go to these tuberculosis resorts. Many of these patients, on arriving at such resorts, acting upon the medical man's advice in their home town, live recklessly and carelessly, and begin to decline in health as soon as they arrive at the supposedly healthy climate. It is not the climate that counts for so much as it is the manner of living. That is the position of the medical world today upon this phase of the tuberculosis problem.

The Congress listened to the words of Dr. Koch, of Berlin, regarding the relationship between human and bovine tuberculosis. It will be remembered that this German bacteriologist, several years ago, at the International Congress on Tuberculosis, meeting in England, startled the medical world with the assertion that bovine tuberculosis, in his opinion, was not transmissible to man. The stir that this statement created was pronounced. Since that time, fact upon fact has been brought for

ward to show Dr. Koch that he is in error upon this subject, and that bovine and human tuberculosis are intercommunicable. At this Congress Koch continued to maintain his position, as originally advanced. Much though he dominated the convention, so far as great attention and respect was paid to whatever he would give out for publication, nevertheless, practically, the united Congress refused to acknowledge the correctness. of his views along this line, and even went so far as to pass resolutions declaring for the unity of bovine and human tuberculosis. Arloing and Courmont, of Lyons, France, stood out above all others in denying the truth of Koch's contention. The clash of theories on the question of the unity or duality of the tubercle bacillus from man and cattle was seen in the conflicting statements of three leaders of medicine in their addresses, to-wit: Dr. Koch, in his address, said, "Up to date, in no case of pulmonary tuberculosis has the tubercle bacillus of bovine type been definitely demonstrated." Dr. Johann Fibiger, of Copenhagen, Denmark, said, in refutation of this, "Now, the wrong of Koch's opinion being generally recognized, one does not forget that the transmissibility of bovine tuberculosis to man is pointed out by extensive investigations from the last few years." Speaking from the standpoint of the American authorities, Dr. M. P. Ravenel, of Madison, Wis., sharply replied to Koch in these words: "On the correct solution of this question depends, no doubt, the health of many children, and even their lives, and I would consider it an extreme misfortune, not only for this country, but to every country on the face of the earth, if any impression should go from this meeting that even the small proportion of deaths due to the bovine bacillus was a negligible quantity." Koch and Fibiger called attention, in their addresses, that it is to an American, Dr. Theobald Smith, of Harvard University, that the medical world owes the knowledge of the morphologic and biologic differences between the human and the bovine tubercle bacillus. In order to give a complete understanding to our readers of exactly what Koch's position on this point is, I will quote his exact words before the Bacteriological Section, where the heated argument that was the only controversial scene of the entire Congress occurred. He said, in part:

The question whether or not human and bovine tuberculosis are identical is, indeed, of high theoretical interest. But the practical importance of the question which concerns the prevention of tuberculosis is of far greater importance. For this reason I will confine myself solely to a consideration of the practical side of the subject.

To Theobald Smith, of Harvard, belongs the credit to have been the first to direct attention to certain differences between the tubercle bacilli found in man and in cattle. It was his work which induced me to take up this same study. In cooperation with Schutz, I have undertaken a series of experiments for which we selected cattle, these animals being specially suited for such work.

The results of these experiments have led me to conclusions which I first communicated to the British Congress on Tuberculosis, in 1901. They are, in substance, as follows:

1. The tubercle bacilli of bovine tuberculosis are different from those of human tuberculosis.

2. Human beings may be infected by bovine tubercle bacilli, but serious diseases from this cause occur very rarely.

3. Prevention measures against tuberculosis should, therefore, be directed primarily against the propagation of human tubercle bacilli.

NOT ASKED TO ACCEPT VIEWS.

I did not expect that my personal views on the relation of human and bovine tuberculosis would be accepted as final, but I asked that the experiments of Schutz and myself be repeated. This has been done by a host of investigators.

The animals used for experimentation must be entirely free from spontaneous tuberculosis. Since the earliest stages of tuberculosis infection can not be recognized with certainty, the source of error arising therefrom is only to be overcome by experimenting on long series of animals. This is especially true of investigations on cattle, as in them tuberculin proves the presence of tuberculosis not immediately after infection, but only after the lapse of a certain time. Experiments conducted on too small a number of animals carry no weight whatever. Single exceptions in extensive series of experiments depend, as a rule, on experimental error. They should be valued accordingly, or the whole series repeated.

USE CULTURE OF BACILLUS.

Inoculation of animals should be made subcutaneously with weighed quantities of a culture of the tubercle bacillus. Experience has shown that the best results for infection are obtained with doses of ten milligrams. Tissue substance must not be used directly, as it contains the tubercle bacilli in irregular distribution. The results obtained thereby are, consequently, not comparable. It is not practicable to use the tubercle bacilli in too large doses, or to make intravenous or intraabdominal injections, as by such applications non-virulent, or even dead, tubercle bacilli may produce lesions resembling tuberculosis, and thus simulate positive results.

Many of my opponents have made strenuous efforts to prove that the tubercle bacilli in man and those in cattle can not be of different species, and they imagine that they can thus refute my contentions. This, however, is a perfectly useless endeavor. I have never held that we are dealing with two distinct species, but have only stated that they differ from each other in certain characteristics, characteristics which are of the greatest importance in combating tuberculosis.

QUESTION OF SPECIES IRRELEVANT,

Whether these differences justify us in speaking of special varieties, or even species, is, from my point of view, quite irrelevant. I am concerned, as I have previously stated, only with the practical significance of the differences between human and bovine tuberculosis.

Others of my opponents have attempted to refute me by showing that the bacillus of the human type may be transformed into the tubercle bacillus of the bovine type, and vice versa, by passages through animals, or by cultivation under artificial conditions. In this connection I can merely repeat that I am interested only in the practical significance of the difference between the two types of tubercle bacilli.

For our purposes, that is, for combating tuberculosis, it is absolutely without significance what changes tubercle bacilli will undergo after being passed through a series of animals, or during cultivation under some artificial conditions. Those

men who consume milk and butter do not hold back and make cultural or animal experiments; they eat them in the fresh, unchanged condition. In my opinion, therefore, we are concerned here with the properties of the fresh and unchanged tubercle bacillus only. I do not deny that cultural transformation may be made with these as well as with other bacteria, but this is a question of purely theoretical value. I shall, therefore, lay it aside.

SUMMARY OF INVESTIGATIONS.

We may now take up the results of recent investigations. I believe that what has come to my knowledge, so far, may be summarized, briefly, as follows:

All competent investigators agree that the tubercle bacilli of human origin differ from the tubercle bacilli of cattle, and that, consequently, we must differentiate between a typhus humanus and a typhus bovinus. The British Commission also admits the existence of three differences, but as some of their cultures showed definite changes in their characteristics after passage through animals and various cultivations, they have differentiated a third group, which they call “unstable.”

As I have repeatedly emphasized, it is not of the slightest importance to us whether, after animal inoculation or breeding experiments, the tubercle bacillus is stable or unstable. What concerns us is its behavior in the fresh condition. I am, therefore, unable to accept this third group of the British Commission, and I am satisfied with their admission that the fresh tubercle bacilli of the human type differ distinctly from those of the bovine type.

HOW BACILLI GROW.

The tubercle bacilli of the human type are characterized by the fact that they grow rapidly and abundantly in a thick layer on glycerin serum. They are virulent to guinea pigs, slightly virulent to rabbits, and almost non-virulent to cattle. The tubercle bacilli of the bovine type grow very slowly and in a thin layer on glycerin serum; they are of equally high virulence to guinea pigs, rabbits and cattle. To my knowledge the bacilli of the human type have never been demonstrated in cattle.

The bacilli of the bovine type, on the other hand, can occur in man. They have been found in the cervical lymph glands, and in the intestinal tract. With few exceptions, however, these bacilli are but slightly virulent for man, and remain localized. The few known cases in which the bovine tuberculosis is said to have produced a general and fatally progressive tuberculosis in man appear to me not to be above suspicion.

PULMONARY IMPORTANCE.

In closing, I have still one point to discuss which seems to me of high importance. Of all human beings who succumb to tuberculosis, eleven-twelfths die of consumption, or pulmonary tuberculosis, and only one-twelfth of other forms of the disease. One would have expected, therefore, that those investigators who are interested in establishing the relations between human and bovine tuberculosis would have searched for bacilli of the bovine type preferably in cases of pulmonary tuberculosis.

This, however, has not been the case. Evidently animated by the desire to bring together as many cases as possible of bovine tuberculosis in man, they have investigated particular cases of gland and intestinal tuberculosis, and have negelected the much more important pulmonary tuberculosis. In spite of the bias under which the researches hitherto have suffered, there yet remain at our disposal a sufficient number of investigations of pulmonary tuberculosis to warrant a provisional expression of opinion.