TOXINS AND ANTITOXINS 77 



as, for example, beef serum, which in doses of 0.5 c.c. will kill a 

 guinea-pig in a few minutes. Dog serum is also toxic for guinea- 

 pigs in somewhat larger doses (i.o to 2.0 c.c.). Horse serum is toxic 

 for cats in doses of i.o c.c. per kilo, and for guinea-pigs in doses of 

 20.0 c.c. per kilo., but man is practically insusceptible, except in 

 those cases of hypersusceptibility in which small doses of serum 

 produce serious symptoms and even death. Such toxic sera con- 

 tain hemolysins and agglutinins in small amounts and reduce the 

 coagulability of the blood, but death is probably due to other factors. 

 Except for cases of natural or artificial hypersusceptibility, the toxic 

 element is destroyed by heat of 56 C. and is removed by 

 animal charcoal. 



