CHAPTER VIII 



THE TOXINS 



MlCROBIAL AND VEGETABLE TOXINS ENDOTOXINS 



Microbial and vegetable toxins Definition Soluble toxins Characters 

 Toxins and diastases : resemblances and differences Incubation 

 Penetration of the body Elective fixation Wassermann's experi- 

 ment Vegetable toxins : ricin, abrin, crotin Production of 

 antitoxins Endotoxins Definition Toxity of microbial bodies 

 Toxin and endotoxin of the cholera vibrio Do anti-endotoxins 

 exist ? Importance of intravenous inoculations. 



MICROBIAL AND VEGETABLE TOXINS 



WE know toxins as properties, not as substances, properties 

 of certain broth-cultures, or properties of the bodies and 

 extracts of the bodies of bacteria. Their nature and their 

 exact chemical constitution are unknown, for they are bound 

 up with albuminoid substances the chemistry of which is still 

 in its infancy. 



The science of toxins is therefore more physiological than 

 chemical, and the chief method of experimentation is on the 

 living body. The quantitative element is introduced by mea- 

 suring the incubation times, the temperature, or the magnitude 

 of the local phenomena, such as oedema and the duration of the 

 symptoms of intoxication. 



In certain cases it has been possible to replace the animal 

 experiment by experiments in vitro, and to measure, with 

 exactitude, certain phenomena, easy to observe, such as the 

 lysis of the red corpuscles of the blood (haemolysis). 



Useful discoveries are much oftener reached by instinct than 



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