134 APPLIED BACTERIOLOGY 



attending the use of antitetanic serum in man have been 

 somewhat disappointing. The reason is not far to seek : 

 the number of immunisation units has probably not been 

 sufficiently high, and the treatment has not been put in 

 operation at a sufficiently early stage in the disease. It is 

 clearly useless in acute cases with a short incubation period, 

 unless employed almost immediately after infection. 



The importance of dose and of early employment of the 

 treatment will be seen from the following : Behring advo- 

 cates the employment of a serum of which 1 gram wiU 

 protect 1,000,000 grams of body weight. A guinea-pig 

 weighing 200 grams would therefore require 0*0002 grams 

 of serum to protect it against the' minimum lethal dose of 

 the toxin, when injected simultaneously. But if infection 

 had already commenced in the animal, 1,000 times this 

 dose would be necessary ; a few hours later 10,000 times 

 this dose would be the minimum amount of serum to 

 protect the animal. The antitetanic serum at present sent 

 out by the Pasteur Institute in Paris has a strength of 

 1 : 1,000,000,000. It is suggested to inject 50 to 100 c.c. 

 in one or two doses. 



Antistreptococcic Serum. — The use of antimicrobic serum 

 in the case of streptococcic infection has recently come 

 into extensive use. This serum was iirst prepared by 

 Marmorek as follows : He found that the virulence of a 

 culture of Streptococcus pyogenes could be enormously 

 ' exalted ' by passing through a number of guinea-pigs, by 

 intraperitoneal injection. By this means the virulence 

 became so greatly increased that if only one or more indi- 

 vidual organisms were introduced into a rabbit, by sub- 

 cutaneous or intravenous injection, a fatal septicsemia was 

 rapidly produced. Small but gradually increasing doses of 

 these highly virulent streptococci were then injected into 

 a horse, and the injections continued over some consider- 



