BACTERIAL POISONS. 47 



From 1882 to 1888, Brieger succeeded in isolating and determin- 

 ing the composition of a number of ptomajins. From putrid flesh 

 he obtained neuridin, C^Hj^Nj, and neurin, C^HuNO. The former 

 is inert, while the latter is poisonous. From decomposing fish he 

 separated a poisonous base, CjH^(NHjj)2, which is an isomer of ethy- 

 lidenediamin, muscarin, C^Hj^NOj, and an inert base, CyHj^Oj, 

 gadinin. Rotten cheese yielded neuridin and trimethylamin. De- 

 composed glue gave neuridin, trimethylamin and a muscarin-like 

 base. In the cadaver, he found in different stages of decomposi- 

 tion, cholin, neuridin, trimethylamin, cadaverin, CjHj^Nj, putrescin, 

 C^HjjjNj, and saprin, CjHj^Nj, all of which are inert. After four- 

 teen days of decomposition he found a poisonous substance, mydalein, 

 and from a cadaver which had been kept at from — 9° to -f 5° for 

 four months, he obtained mydin, CgHjjNO, the poisonous substance 

 mydatoxin, CjHjjNOj, also the poison methyl^uanidin. From 

 poisonous mussel he separated mytilotoxin, CgHj^NOj. 



During the later years of the ninth decade of the nineteenth cen- 

 tury, chemists began to study the products of bacterial growth in 

 pure cultures. In this work, Brieger, following a method devised 

 by himself, succeeded in isolating a number of basic substances, 

 which were at that time supposed to be the specific toxins of certain 

 diseases. He obtained typhotoxin from cultures of the typhoid bac- 

 illus, and four crystalline bodies in growths of the tetanus organism. 

 In 1888 Roux and Yersin made an important contribution in their 

 classical work upon the diphtheria toxin, and two years later Brieger 

 and Frankel confirmed these discoveries and extended this line of 

 research. Sewall, Salmon and Smith opened up a fruitful field for 

 investigation by showing that immunity can be secured with chem- 

 ical poisons, the first-mentioned having worked with snake venom, 

 while the others used sterilized cultures. A few years later this 

 work was taken up and greatly advanced by Ehrlich in his now 

 classical studies on immunity, which were first made with the poison- 

 ous principles of castor bean and jequirity, and later extended to 

 bacterial products. In 1887 Fodor made his second contribution on 

 the germicidal action of the blood in vita. This work, developed by 

 the researches of Nuttall, Buchner, Metschnikoff, Pfeiffer, Ehrlich, 

 Bordet and numerous others, has greatly advanced our knowledge of 

 the manner in which the animal organism protects itself from bac- 

 terial invasion, and has given us some practical tests, as the Widal re- 

 action, which are useful in the diagnosis of diseases. In 1892, blood 

 serum therapy, which had been attempted before by Babes and Tiz- 

 zoni, was brought into prominence by the researches of Behring, and 

 confirmed by Roux in 1894. As a practical result of this line of 

 research we have the antitoxin treatment of diphtheria, probably the 

 most brilliant discovery yet made within the domain of curative 

 medicine. All of these subjects will be dwelt upon in detail in sub- 

 sequent chapters. 



