VACCINATION 77 



in order to prevent septicemia. Its effect is to increase phagocy- 

 tosis and cause bacteriolysis. No satisfactory standard has been 

 devised. Dosage varies but a safe guide is to inject under the 

 meninges 75 percent as much as the fluid removed at lumbar 

 puncture. Intravenous dosage should be 20-50 c.c. The anti- 

 serum probably has no prophylactic value. 



Anti-plague Serum. Yersin, a French bacteriologist, treated 

 horses with living cultures of plague bacilli, and after a long period 

 of immunization used a serum which either effectually vaccinated 

 an individual against the plague, or greatly modified the disease 

 after it had once begun. 



The action of the serum is bactericidal, as well as anti-toxic. 

 The dose varies with the stage of the disease; 20 c.c. is an effective 

 prophylactic dose, while from 20 to 300 c.c. have been used often 

 as curative doses. 



VACCINATION 



By the use of attenuated, or killed microorganisms, it is possible 

 to effectively vaccinate men and animals against many diseases, 

 notably, small-pox, hydrophobia, plague, cholera, typhoid fever, 

 anthrax and quarter-evil. 



Any of the bacterial products used as prophylactics are some- 

 times called vaccines, the word being borrowed from small-pox 

 vaccine. It is better to use the word bacterin for the purpose, 

 even when they are given prophylactically. Bacterin is employed 

 for the dead bacterial masses used therapeutically. Sensitized 

 bacterins are vaccines that have been exposed to the action of the 

 respective anti-sera before their use. It is the purpose of this 

 procedure to prepare the organisms by combining them with the 

 homologous anti-bodies so that when injected they have only to 

 combine with complement to begin their immunizing effect. 

 Theoretically this is correct but the practical value has not been 

 fully confirmed. 



