No. 4.] CATTLE COMMISSIONERS' REPORT. 565 



arrived at in a short time, it will be a great step in advance. 

 Keirle ("New York Medical Journal," Vol. 60, page 27) has sug- 

 gested the use of mice for this purpose, claiming, from the results 

 of his, experiments, that a few drops of fluid, in which was sus- 

 pended a little of the brain of a rabid animal, inoculated at the 

 root of the tail, produced the disease in from seven to eleven days. 

 Upon study of his work it was found that he had only used ma- 

 terial coming from experimental animals, in which the virus was 

 tolerably constant. It was deemed advisable, therefore, to try it 

 in the ordinary' cases of street rabies, as thej'^ came to the labora- 

 tory. In this work I was kindly assisted by Dr. Langdon 

 Frothingham. The results of our work can be briefly stated as 

 follows : — 



As a rule, the mice died more quickly than the rabbits, but 

 there were marked exceptions to this. The symptoms were by no 

 means as clear, and were often only of a few hours' duration be- 

 fore death. When this is taken into account, with the liabilty of 

 such quick-moving little animals to escape, and the difficulty of 

 identification, they were found to be practically of no advantage 

 over rabbits. 



Another series of experiments had in view the isolation of the 

 virus. It has never been clearly shown what this is, and, although 

 there are many reasons which render it probable that it depends 

 upon the action of the bacteria, still, none have ever been shown 

 that can reproduce the disease. It has, therefore, suggested itself 

 that the poison may be of the nature of a chemical ferment ; and 

 an attempt was made to obtain this by means which should ex- 

 clude the possible action of bacteria. 



The brains of two rabbits which had died from rabies were 

 divided into four equal parts and allowed to macerate for about 

 four days in a cold place, as follows: No. I., in ether; No. II., 

 in a mixture of ether 65, alcohol 15 and chloroform 20 parts ; No. 

 III., in benzole ; No. IV., in rhigolene. These extracts were then 

 passed through a Pasteur filter, to remove any bacteria that might 

 have been in the original brain substance ; the ethereal and other 

 solvents were removed by careful evaporation in vacuo at a low 

 temperature, and towards the end of the process a little sterilized 

 water was added, to prevent complete desiccation, which it is well 

 known destroys the virus. From each of the four extracts a 

 considerable residue was thus obtained. Distilled water to the 

 amount of about 10 cubic centimeters was added to each, and the 

 substance, as finely divided as possible by breaking up with a 

 glass rod, was suspended in it. 



Two rabbits were inoculated in tlie usual way from each of the 

 three mixtures, with the following results : No. I. A rabbit dies 



