BACTERIAL ACTIVITY 175 



BACTERIAL POISONS. 



The knowledge of these is by no means complete, so 

 that sharp distinctions between various kinds cannot be, 

 at present, depended on. The first to study their pro- 

 duction was Brieger, and it was while so engaged that he 

 was led to the discovery of the ptomaine poisons. These 

 bodies, however, did not, on injection, reproduce the 

 symptoms of diseases associated with the bacteria con- 

 cerned in their production, and so the ptomaines are not 

 nowadays classed as true bacterial poisons. Roux and 

 Yersin, in 1889, filtered broth- cultures of B. diphtherias 

 through unglazed porcelain (Chamberland filter), and 

 showed that the filtrate was bacteria free, and yet on 

 injection the filtrate produced practically the same effects 

 as the injection of the living bacilli. From this it was 

 inferred that the filtrate contained the toxin of the 

 diphtheria bacillus. The same method applied to other 

 bacteria yielded no such result in most, and so the con- 

 ception was reached that some bacteria secrete or excrete 

 poisons which are soluble in the media in which they are 

 grown, and some do not. Of the former class, diphtheria 

 and tetanus are the types ; of the latter, the tubercle 

 bacillus may be taken as a type, but the class is a very 

 large one, including all the bacteria except diphtheria, 

 tetanus, botulinus, and the anaerobes generally (some to 

 only a small extent). Other bacteria, such as dysentery 

 and cholera, are said to produce soluble poisons, but the 

 results are still discordant. As a consequence of these 

 findings, and of the further observation that, in the 

 bacteria not secreting soluble poisons, the injection of 

 dead bacteria could reproduce many of the characteristic 

 lesions of the disease associated with them in the living 

 state, the division of bacterial poisons into two groups 

 has arisen, viz : 



1. Extracellular toxins, true toxins, or soluble toxins. 



2. Intracellular toxins, endotoxins. 



After the removal of these bodies from the bacteria, a 

 certain proteid residue remains, which, on injection, gives 

 rise to localized reactions. Buchner calls this residue 

 " bacterial protein," and believes it to be the same in all 



