that the sarcoma of rats was contagious. Leo Loeb, of the University of Pennsylvania, spent the summer of 1902 at the laboratory studying the rat sarcoma and had in his possession a number of rats suffering with sarcoma of the thyroid, all of which had developed in the same cage in the Chicago Polyclinic Laboratory. These were kept in two large and many small cages. On his return to Philadelphia the small cages were sterilized by heat, while the large cages were merely cleaned and put away. For over a year no rats or mice were kept at the laboratory in Buffalo, but at the end of that time. a supply of healthy rats was obtained for another purpose entirely. Within a few months two rats which were confined in the large cages developed sarcomata and during the following year several more were observed in the same cages. No tumors made their appearance among the occupants of the small cages which had been previously sterilized.

This is all the more interesting in view of the fact that dealers in pet animals throughout the country are continually on the alert for the appearance of tumors, having in mind the great demand for them at the Research laboratories, and that but a half dozen tumors or so have been found in the thousands of mice and rats bred annually for sale.

The tumors of mice are mostly carcinomata of the breast and make their appearance in the old females which have been kept for breeding purposes.

Healthy mice kept in the same cage with carcinomatous mice have in a number of carefully recorded cases developed the identical lesions. This has been partially explained on the ground that the females nurse the young indiscriminately and that the infection could thus be transferred from one breast to the other.

"Cancer houses" have been cited in corroboration of the parasite theory with reference to the human race, but in a careful study of this phase of the problem the question of heredity cannot be eliminated.

With the foregoing data in mind, a most painstaking study of the specific cause of cancer has been undertaken by workers throughout the whole world.

The vegetable kingdom has yielded some interesting knowledge on this subject. The analogy between the tumors appearing on certain vegetables and the tumors of man was early recognized. On the roots of the cabbage, turnip, cauliflower, and others of the same class there appear in certain sections of the country a tumor of bizarre shape and varying size. It causes a wilting and stunting of the plant somewhat similar to the cachexia of cancer. The cause has been recognized as the Plasmodiophora Brassicae, and the disease has been called "club foot" from its appearance. Furthermore, its prevalence in the so-called "cancer districts" has been noticed repeatedly. Its inoculation into animals has produced swellings and tumor formations, which on section possessed certain points of similarity to the malignant tumors, and the spores of the parasite could be demonstrated.

Cell inclusions.

Since the advent of the microscope attention has been directed repeatedly to certain bodies embedded in the cytoplasm of the cells of malignant tissues, hoping to find in them the cause of cancer. They have been called "Plimmers bodies", or, from their similarity to the eye of a bird, "birdseye inclusions". Probably more effort has been expended on these inclusions than on any other phase of the question, and with this result, according to Gaylord, that, with the same fixing and staining methods the spores of the plasmodiophora brassicae after inoculation into animal tissue and the "birdseye inclusions" of spontaneous cancer cells, appear indistinguishable under certain conditions.

This would seem to indicate only a more or less similarity of process, and while no conclusions can be drawn from such an elementary step, nevertheless one more stone has been laid in the foundation of the study of cancer.

The most startling revelation in the search for the etiology of cancer has again arisen from the work of Gaylord at the Buffalo laboratory. In 1905 there were found in the cells of mouse tumors certain fine rod-like structures, which were held by most men to be artifacts produced in the fixing and staining of the tissues.

Levaditi, in 1906, demonstrated the presence of the Spirochaeta Pallida in syphilitic tissues by his own method of staining, and the Spirochaeta Pallida from that time was accepted as the long sought cause of syphilis. By employing the same method of staining, Gaylord demonstrated a characteristic spiral organism in ten consecutive cases of spontaneous mouse cancers. Sixteen transplanted tumors showed the same organism, and it was also demonstrated in the living state in fresh cancer tissue. It was found to be frequently motile. The measurements of the fresh and stained organisms corresponded. He found the greater numbers in the most virulent cancers. In cancers contaminated by bacteria no spirochaeta were found, and although a thorough and exhaustive search was made of healthy mouse tissue the organism could not be demonstrated.

By technical staining and measuring methods, it was differentiated from all other organisms of like nature found in mouse blood and tissues.

Dr. Gaylord very modestly states that while these observations do not prove the etiological relation between this "Spirochaeta Microgyrate" and cancer of the breast in mice, it is at least very suggestive.

In opposition to the parasitic theory, let me again quote Bland-Sutton: "The greatest feature which distinguishes carcinoma from all infective diseases is its property of producing secondary deposits, which reproduce the structural details of the organ or tissue primarily affected, and this is one of the most surprising facts in the whole range of pathology. In the case of the typical infective diseases like tuberculosis, the infective agents, the T. B., are transported by the bloodstream and we are prepared to find a colony of the bacilli flourishing in the cancellous tissue of the calcaneum or the body of a vertebra, and these will cause tissue lesions identical with those which would be formed if the primary tuberculosis lesion was situated in muscle, brain, lymph gland, lungs, or kidney. This means that the bacilli are transported but there is no actual transference of tissue."

The histological study of carcinoma has taught that the dis

ease originates in the epithelial cells, and these elements of cancerous formation have been most perseveringly studied with the aid of the microscope and anilin stains. So far no method however ingenious has been found which will successfully cultivate the cancer cells. Many organisms have been exploited, but so far none have been found which will satisfy Koch's postulates, which are, namely:

(1) The Micro-organism must be present in all cases of the disease.

(2) It must be capable of cultivation apart from the ani

mal.

(3) It must reproduce the disease when inoculated into healthy animals.

However, it must be borne in mind that Koch's postulates were formulated for the vegetable micro-organisms only, and can hardly be said to govern the animal parasites, which require, in many instances, a partial life cycle in some intermediary host.

The hematozoon of malaria cannot be cultivated apart from the animal, nor will it, aside from the aid of the mosquito, cause malarial fever when inoculated into a healthy animal; yet, though it does not satisfy the second or third of Koch's postulates, who can gainsay the statement that the parasite is the specific cause of malaria?

In the present status of cancer research, no definite conclusions may be drawn, but when the specific cause has been discovered no doubt the specific remedy will be at hand. But in the meanwhile we must continue the fight with the weapons we now have. And so the question is a pertinent one of what does this armament consist?

Treatment.

Perhaps the oldest method of combatting the dread condition is the actual cautery. In the very earliest times this consisted of the red hot iron, and in those pre-anaesthetic days the cure must surely have been the equal of the disease in the suffering inflicted. Later the heated knife was but a slight improvement, while the agony caused by the bone or wooden

knife dipped in fuming acids can only be imagined. To-day the cautery is only used in conjunction with other methods.

The use of superheated air as a destroyer of tissue has been recommended by Dr. Hollander, of Berlin, for two reasons, namely: The temperature is under better control, being regulated by the rate at which air is forced through a coiled tube over a Bunsen burner, and the fact that diseased or abnormal tissue succumbs more readily to the effect of heat than does normal healthy tissue. Thus it was claimed that the cancer cells would be destroyed without so much damage to the sound tissue as in the case of the actual cautery, which is no respecter of protoplasm, destroying alike the good and bad. The air cautery has never attained general acceptance by surgeons. X-Ray.

Great interest was aroused by the statement that the application of the Röentgen rays would be the long sought cure. Subsequent tests by competent men have determined that the beneficial effects are only applicable to superficially situated cancer.

Proper exposure to X-Ray and to radium not only cures this form of the disease, but leaves a scar remarkably like normal skin.

The pain of deep seated lesions in the viscera, however, has been very greatly relieved by moderate exposure to the X-ray.

Drugs.

Salicylate of soda and Chian turpentine have claimed much attention in recent years, both drugs seeming to limit the discharge for a time, but, as for presenting certain cures, they have gone forever to join forces with the powdered oyster shells, violet leaves, and ashes of old burnt shoes once so highly recommended.

Toxin and serum therapy.

This method was introduced by Dr. William B. Coley, of New York, and has obtained prominence enough to deserve special mention. The best results have been obtained by Dr. Coley himself, but other surgeons have found the treatment satisfactory in a certain percentage of cases.

It has often been observed that when erysipelas attacks the