PROTECTIVE INOCULATIONS. 325 



some instances to as much as ten per cent have resulted from the in- 

 oculations. These are ascribed by Chambeiiand to secondary infec- 

 tion, through the inoculation wound, with other pathogenic bacteria. 



Jakobi (1888) reports the results of inoculations made in 1887 and 

 1888 with "vaccines" obtained from Pasteur's agent in Paris. His 

 results agree with those previously reported by Lydtin in showing a 

 smaller loss, as & result of the inoculations, among young pigs than 

 among older ones over sixteen weeks. The loss among young pigs 

 was only 1.3 per cent. The animals which survived subsequently es- 

 caped infection, while others not inoculated, associated with them, 

 succumbed to the disease. 



Hutyra has given the following statistics of inoculations made in 

 Hungary during the year 1889, with " vaccines " obtained from the 

 Pasteur laboratory in Vienna: 48,637 pigs were inoculated on 117 

 different farms. Of these 143 (0.29 per cent) died between the first 

 and second inoculation. After the second inoculation 59 animals died 

 (0.1 per cent). During the year following the inoculations, 1,082 in- 

 oculated pigs died of Rothlauf. Before the inoculations the annual 

 loss in the same localities is said to have been from 10 to 30 per 

 cent. Upon one farm 220 pigs which had been inoculated were as- 

 sociated with 1,500 not inoculated. The loss among the latter was 

 50 per cent; among the former 2.27 per cent. 



In a later communication (1894) Jakobi gives the following results 

 of inoculations made since by the same method: 1889, inoculated 

 133, loss 5; 1890, inoculated 151, loss 2; 1891, inoculated 158, loss 

 0; 1893, inoculated 223, loss 0; 1894, inoculated 145, loss 4. Total 

 inoculated, 1,036; total loss, 14. These inoculations were made upon 

 19 different farms, and principally upon pigs less than four months 

 old. The inoculated pigs were isolated to prevent the communication 

 of the disease to other unprotected pigs. 



Inoculations with Blood Serum of Immune Animals. The experi- 

 ments of Lorenz, commenced in 1891, seem to establish the fact that 

 there is an antitoxin in the blood of animals which have an acquired 

 immunity against this disease which may be used for producing im- 

 munity in other animals, or for the cure of the disease in animals 

 already infected. In his latest communication (1894) Lorenz says : 



% ' When I read in the journals of the discovery of Behring and Kitasato 

 that the blood of animals immunized against tetanus, when injected beneath 

 the skin of other animals, gave them an immunity against tetanus, I had in 

 my possession rabbits which were immunized against Rothlauf. I took from 

 one of these some blood from the ear vein, injected it under the skin of a 

 mouse,, inoculated this latter with a Rothlauf culture, and made the dis- 

 covery, in this and a series of subsequent experiments, that the blood of an 



