tive proof is lacking. The definite morphology of the structures and the constancy of their occurrence, tend to substantiate such a belief. Three hypotheses may be cffered to explain their occurrence: (1) Degenerations, or artefacts of the cell protoplasm; (2) phagocytosis, that is, the nerve cells attracting and enveloping certain other normal histological structures, as red blood corpuscles; (3) the specific micro-organism of the disease.

As to the first hypothesis, Negri states that artefacts can not be made by any method of preparation to simulate these bodies, and his conclusions are corroborated by all observers so far as I am able to determine. The question of degenerations should be carefully considered. While it is the general opinion that no form of metamorphosis of the cell protoplasm could account for structures so constantly found in certain cells, so definite in shape and uniform in staining reaction, yet the possibility of the toxin causing a specific form of degeneration should be kept in mind.

Poor states that in a case of tetanus minute eosinophilic granules were found in the Perkinje cells of the cerebellum, but to an experienced eye they would not be mistaken for Negri bodies. Nerve cells in all stages of degeneration show no such structures as are found in rabies. Negri bodies retain their characteristics in cells in all stages of degeneration, and Negri states that they even resist the putrefactive process.

The theory of phagocytosis is less tenable than that of specific degeneration. To the inexperienced erythrocytes are more likely to be mistaken for Negri bodies than any other histological structures, as they are about the same size, though usually larger, and are eosinophilic in reaction. This fact suggested the hypothesis that Negri bodies were red blood corpuscles phagocytized by nerve cells.

While

To me this view is untenable for many reasons. both Negri bodies and erythrocytes stain red, the former are of a darker color. In fresh preparations the bodies are hyaline and have not the slightest resemblance to red blood cells, and in sections stained with osmic acid they show up black, while the latter remain unstained. It is also impossible to conceive of a phagocytized red blood corpuscle increasing in size and developing a nucleus. Phagocytized red blood corpuscles in the spleen show no resemblance to Negri bodies, but are found as fragments and in various stages of degeneration.

Both direct and indirect evidence in favor of these structures being the specific germs of the disease may be said to exist. As stated by Bertarelli: "In more than a thousand tests the Negri bodies were never found in animals free from rabies as determined by inoculation of rabbits. On the other hand, they were always found in infected animals with three exceptions, and in these only a part of the nervous system had been examined." It may be said that in all cases of rabies if every part of the nervous system were examined, these bodies would invariably be found. All observers agree that Negri bodies are never found in other diseases, even in those where the degenerative changes in the nerve cells are pronounced. Judging from analogy, we must admit that rabies is caused by a specific micro-organism, and from its behavior to heat, chemicals and culture media, we are probably justified in believing it to be a protozoan.

The virus is destroyed in a few minutes at a temperature of 110 degrees F. Two per cent. carbolic acid renders it inert in a few seconds, and it is rapidly destroyed by any of the weaker antiseptics. It retains its virulence for weeks or months in neutral glycerine. Glycerine that

is slightly acid destroys the virus. It can not be grown en any known culture medium.

Like many protozoan diseases, it is communicated through the saliva. We now know that malaria, mountain fever, cattle fever and probably yellow fever, are protozoan diseases, and are all communicated through the saliva of infected mosquitoes, ticks, etc. While it is true that the virus of rabies does not pass through an intermediate host, but directly from animal to animal, yet the fact that it is eliminated by way of the salivary glands is suggestive of the protozoan nature of the organism. So, from indirect evidence in our possession, the specific germ of rabies is probably a protozoan, and as Negri bodies resemble protozoa, we are justified in assuming them to be the causative factor in this disease.

Whether or not we regard the bodies discovered by Negri as the specific cause of rabies, their value as a means of rapid diagnosis is now generally recognized. When the brain of an animal is examined and Negri bodies are found, the evidence is considered positive and a diagnosis of rabies is made. More than one thousand tests, confirmed by the inoculation of rabbits, have now been reported, and not a single exception has been found. At the Georgia Pasteur Institute, within the last eighteen months, I have demonstrated Negri bodies in forty-two dogs and three cats, and in every instance the rabbits inoculated died of typical rabies. In three cases where the inoculation test resulted positively, no bodies were found, though only the hippocampus major was examined, and the animals were killed in the first stages of the disease. In fifteen dogs and two cats, proven not to be rabid, no such structures could be demonstrated.

In conclusion, it may be stated that we now have a 1eliable method by which the diagnosis of rabies in ani

mals can be made in a few hours. It has many advantages over the old method, the inoculation of rabbits. Much time is saved and the patient relieved of much susfense. At present I always inoculate one or two rabbits to corroborate Negri's test, and if the bodies can not be found rabbits should invariably be inoculated to prove conclusively the absence of rabies. Dr. Negri has given us a most valuable diagnostic method, and it is the consensus of opinion that he has also discovered the specific micro-organism of rabies.

DISCUSSION ON DR. BRAWNER'S PAPER.

Dr. Henry R. Slack, of LaGrange: At the last meeting of the Medical Association of Georgia, held in this city, I read a paper on hydrophobia, its prevention and treatment, and at that time the distinguished dean of the Medical Department of the University of Georgia (Dr. Foster) took issue with me. I refer to this now, as he is not present to-day, having answered the long roll-call. He did not believe in rabies. The paper I presented was based on the work of Nelis and Ravanel, showing that in this disease there was a hyaline degeneration of the nerve cells. This has since been proven to occur in other diseases than rabies, and is not considered so valuable as a test, although they have found it in nearly every instance of rabies. But the work of Negri seems to be a classic. There are some few exceptions to it. We have proved it in our institution in Atlanta. There were only two cases in which there was failure to find Negri bodies after the inoculation of rabbits which showed rabies. This places hydrophobia where it should belong, and where all physicians accept it, as a disease which is transmissible to man.

At the time Dr. Foster took issue with me he had the

support of two distinguished medical writers, Loomis and Douglas. Dr. Loomis, as many of you doubtless know, has been converted to the hydrophobia theory by a sad personal loss. His son was passing along Fifth avenue, New York, one afternoon and was bitten by a dog. There was a crowd of people who saw the boy bitten. The wound was not cauterized. Dr. Loomis refused to have the boy treated. He wiped the wound, and in less than six weeks the boy died from hydrophobia. Since then Dr. Loomis has written articles to counteract the bad impression he had previously created by saying that there was no such a disease, and in fact he regretted very much the position he had taken in the matter.

This paper of Dr. Brawner's is very important, as it will save many a person who is bitten by a dog supposed to be rabid. It takes from fourteen to eighteen days to carry on the treatment after a patient has been bitten. Now, with our present improved methods, in twenty-four hours a stain can be made and we can determine whether the case is one of rabies or not, and for that reason this paper is very important.

ease.

Dr. Claude A. Smith, of Atlanta: I am very much interested in this paper from the fact that I have been conducting a series of experiments with reference to this disWhether this is the only causal agent of rabies or not, is not fully determined. Like the spirocheta of syphilis, it is not present in all cases or in all reports. We have not been able to cultivate it in any culture media, and the fact that the organism, as reported by some investigators, will pass through a porcelain filter would indicate that it is not the organism itself, but probably some product of the organism. But the fact that it is constant indicates it is of value in making an early diagnosis, which has been so difficult in the past. As to