164 MANUAL OF BACTERIOLOGY. 



firmly united to the cells. Toxins, therefore, are very peculiar 

 bodies, behaving like ferments in requiring considerable time 

 to produce effects, and acting like unorganized poisons in being 

 used up in the tissue changes which they produce. Certain 

 substances derived from the vegetable kingdom behave in the 

 same manner as bacterial toxins; ricin, abrin and robin are 

 examples of these. The poisons of scorpions and snakes are 

 also poisons which act like toxins. Other properties of toxins 

 will be considered in connection with antitoxin. 



Although, as has been stated, the toxins have not been isolated 

 in a pure condition, they have, nevertheless, been obtained in 

 some cases in an extremely concentrated form. Brieger and 

 Cohn obtained a toxin from tetanus bacilli of which 0.00000005 

 gram killed a mouse weighing 15 grams. Roux and Yersin 

 obtained a toxin from diphtheria bacilli of which 0.00005 gram 

 was capable of killing a guinea-pig. These figures indicate 

 the extremely poisonous character of these toxins. Such 

 properties permit bacteria growing in a comparatively limited 

 area to act upon parts of the body remote from the focus of 

 infection. 



A curious and unexplained effect of some toxins is the production of minute 

 areas of necrosis in certain viscera, as the liver. Such " focal necroses " have 

 been observed to be formed by the poisons of the bacilli of diphtheria, of typhoid 

 fever, and of the Micrococcus lanceolatus of pneumonia, and following the 

 injection of abrin and ricin. 



Besides the poisonous substances produced by the bacilli of diphtheria and 

 of tetanus, toxic substances have been obtained from the spirillum of cholera, 

 the bacillus of typhoid fever, the Bacillus coli communis, the bacillus of bubonic 

 plague, Bacillus pyocyaneus, Streptococcus pyogenes, and Staphylococcus py- 

 ogenes aureus. The extract from cultures of tubercle bacilli, called tuberculin, 

 and that from glanders bacilli, called mallein, will be spoken of in connection 

 with the bacteria themselves. Vaughan * has succeeded in cultivating anthrax 

 bacilli, colon bacilli, and other bacteria on large surfaces of solid media, so as to 

 secure quantities of the bacterial cells sufficient for extensive chemical tests. 

 The toxin of the colon bacillus proved to be a very stable substance, and resistant 



* Journal American Medical Association. September 3, 1904. 



