VACCINE-THERAPY 163 



order to strengthen our position it was necessary to carry out 

 tests other than experimental inoculations — namely, agglu- 

 tination tests and protective inoculations. The agglutination 

 tests were carried out on the following serums : From dogs 

 suffering with the disease spontaneously contracted, from 

 dogs experimentally infected, from dogs immunized to the 

 live organisms, and also those immunized to dead cultures. 

 These were tested repeatedly on the same strain and on 

 different strains. They all gave positive agglutinations, 

 with but one exception ; in this case the dog was an old 

 one, and had probably suffered with the disease. The 

 serum from the dogs suffering from the disease spontaneously 

 produced, as those found on the streets, gave an agglutina- 

 tion ranging from 1 in 40 to 1 in 800. The serum from 

 the dogs experimentally infected gave an agglutination 

 from 1 in 100 to 1 in 600; while those immunized to live 

 and dead cultures, gave a reaction from 1 in 800 to 1 in 

 4,000. The serum which gave the reaction from 1 in 4,000 

 was tested against several strains of the bacillus, and the 

 results ran from 1 in 600 to 1 in 6,000. Two dogs were 

 given one injection of the live organisms each, one intra- 

 venously, and one subcutaneously, and the agglutination 

 reactions ranged from 1 in 100 to 1 in 600. Following 

 the injections of the last dogs, the only marked symptom 

 was diarrhoea. This again emphasizes the symptom upon 

 which I have previously laid so much stress. In all of 

 these agglutination tests we used, as controls, blood of 

 dogs which had never had the disease. They invariably 

 gave negative results. 



" The protective inoculations were also very convincing, 

 and proved to our entire satisfaction that we were dealino- 

 with the specific bacillus. I will quote from my second 

 article in this connection : ' Forty dogs were used in all ; 

 nine were immunized with live cultures, while fourteen 

 were saved as controls. All of these dogs were exposed to 

 at least three dogs suffering with typical symptoms of the 

 disease, including the respiratory, abdominal, and nervous 



