42 ACTIVE IMMUNIZATION 



b. Rapid Immunization. 



Rabbit II. 



8./IV. 1905 Injection of 4 c.cm. of natural swine pest aggressin subcutaneously. 

 lo./IV. Animal shows slight ill effects. 



I3-/IV. Perfectly active. 



26./IV. ist infection: i/io loopful of swine pest culture subcutaneously. 



i6./VL 2d infection: i loopful of swine pest culture intravenously. 



Animal remained active. 



Controls. 



Rabbit III. 



26./IV. 1905 1/10,000 loopful of swine pest culture subcutaneously. 

 2 7 ./IV. f. 



These experiments prove conclusively that by the method described 

 above it is possible to attain a high grade of immunity. In this connection, 

 however, it is very important to adhere to what Bail pointed out, namely, 

 that a long period should elapse between the last inoculation with the aggressin 

 and the first injection; the reason for that being, that during the period of im- 

 munization, and following it for a long time, there is a condition of hyper- 

 susceptibility to infection. 



Example of Active Immunization with Artificial Aggressins. 



Rabbit i. 



3-/VI. 1905 ist injection: 4 c.cm. of watery extract of swine pest bacilli subcutane- 

 ously. 



I4./VI. 2d injection: 2 c.cm. of watery extract of swine pest bacilli subcutane- 



ously. 



2 5.7 VI. Removal of some blood. 



4./VII. 3d injection: 3 c.cm. of watery extract of swine pest bacilli subcutane- 



ously. 



2I./VII. Infection: i/io loopful of swine pest culture subcutaneously. 



3./X. Animal alive and healthy. 



Rabbit 2. 



ig./VI. 1905 ist injection: 2.5 c.cm. of serous extract of swine pest bacilli subcutane- 

 ously. 



9./VII. 2d injection: 2.0 c.cm. of serous extract of swine pest bacilli subcutane- 



ously. 



I2./VII. 3d injection: 4.0 c.cm. of serous extract of swine pest bacilli subcutane- 



ously. 



24./VII. ist infection: i/io loopful of swine pest culture subcutaneously. 



22./IX. 2d infection: i loopful of swine pest culture intravenously. 



Animal remains perfectly well. 

 Rabbit 3. 



i6./VI. 1905 Injection: 2.5 c.cm. of watery extract of swine pest bacilli subcutane- 

 ously. 



