4S8 THE WAR WITH THE MICROBES. 



showed that volatile and nonvolatile substances, ale aline in character, 

 could be obtained from various portions of the animal body, often from 

 fresh material and also from the cultures of bacteria. These ptomaines 

 were found to resemble the alkaloids in their chemical reactions. 



In 1882-83 Brieger succeeded in separating and determining a num- 

 ber of these ptomaines, from the brain, from fish muscarin, from decom- 

 posed glue, neuridine and dimethyl amine, etc. From pure cultures of 

 the typhoid germ he obtained a substance, typhotoxin, which produced 

 typhoid symptoms, and from cultures of the tetanus germ tetanin, 

 which caused convulsions. The presence of similar poisonous bases 

 was demonstrated in cultures of the cholera, hog cholera, anthrax, 

 pyogenes aureus and like active bodies were isolated from cheese, milk, 

 ice cream, sausage, and other foods which had caused sickness. 



The isolation of these poisons from bacterial cultures gave rise to the 

 belief that they were the bodies which caused the fatal effects of dis- 

 ease. But while in many instances they produced the characteristic 

 symptoms, in others they were not sufficient to account for all the 

 phenomena. For example, from cultures of the tetanus germ it was 

 possible to isolate a base that had but slight poisonous properties, 

 while the culture liquid from which this was obtained after all the germs 

 had been removed was ten thousand times more poisonous than the 

 base secured. Xonpoisonous ptomaines were also obtained from cul- 

 tures of disease-producing bacteria, and, in fact, the majority of 

 ptomaines were found to be nonpoisonous. 



The next question was, If in the culture liquids freed from bacteria 

 poisonous substances are obtained, and if they do not belong to the 

 class of x^tomaines, how shall they be identified and classified ? In 1886 

 Mitchell and Beichert, while studying the venoms of serpents, noted 

 that these poisons belonged to a class of bodies different from the 

 ptomaines, viz, to the group called proteids. Shortly after, Boux and 

 Yersin, in their studies upon the diphtheria poison, demonstrated that 

 this was a substance which resembled the ferments and were led to 

 think that an enzyme, as it is called, a substance like pepsin, was the 

 active poison, and that this enzyme was in some way elaborated by the 

 germ. Other investigators had found a similar substance in tetanus 

 and hog cholera cultures, and a reinvestigation by Brieger of a number 

 of bacterial cultures showed that by precipitation with ammonium 

 sulphate and alcohol very poisonous substances giving proteid reactions 

 could be obtained. Proteids of various characters belonging to dif- 

 ferent classes were obtained from cultures of many bacteria. About 

 this time it was shown that certain plants of a higher order contained 

 poisonous bodies of a like proteid character. An albumose abrin was 

 obtained from the Jequirity seeds and ricin from the castor-oil bean. 

 These were intensely poisonous, tWooo °f a grain of abrin being suffi- 

 cient to kill an animal weighing one kilogram, or the T ^o of a grain 

 should be a fatal dose for a man weighing about 130 pounds. 



