150 BACTERIAL POISONS. 



further dose for a period of twelve hours. The second 

 albumose is the poisonous principle of snake-poison. 

 Sewall, in 1887, published a very interesting research on 

 acquired immunity against snake-poison. He showed that 

 it was possible, by the injection of a few minute doses, to 

 give pigeons such a tolerance of this substance that, three 

 months after the treatment, they were able to stand what 

 would otherwise be seven times the lethal dose. He sug- 

 gests in his paper that, by inoculation with the ptomaines 

 produced by bacteria, it may be possible to protect animals 

 against their disease- producing powers, although the re- 

 markable case of tolerance he had discovered suggested that 

 not ptomaines, but albumoses, were the substances con- 

 cerned in giving immunity against a disease;^ for I sug- 

 gest that this fact — that the only cases of tolerance known 

 which resemble the tolerance implied in disease-immunity 

 are cases of tolerance against albumoses — strongly suggests 

 that immunity against a disease is immunity against an 

 albumose produced by the microbe." 



In conformity with the above-stated theory, Hankin 

 prepared, as we have already stated, from cultures of the 

 anthrax bacillus a poisonous albumose, which, when em- 

 ployed in small doses, gives immunity ; in large doses, 

 proves fatal. Hankin endeavored to separate any ferment 

 that might be present and to which the immunity might 

 possibly be due. A quantity of lime water was added to 

 a solution of the albumose and the lime precipitated by the 

 addition of phosphoric acid. Theoretically, the precipitate 

 should contain any ferment present, and the immunity- 

 giving property of the albumose would be diminished by 

 the amount of the ferment thus removed, in case the im- 

 munity be due to the ferment. However, the albumose 

 was found to have lost none of its immunity-producing 

 power. From this Hankin concludes that the albumose 

 is the real immunity-producing agent. He does not in- 



' We would suggest the fact that in 1887 it was not known that bacteria 

 produce albumoses, and at that time the term "ptomaine" was employed 

 to indicate all the bacterial poisons. 



