THE NATURE OF TOXINS 165 



as evidence of the existence of a special group of toxins, it has 

 been stated that a special type of immunity against the 

 aggressins can be originated. Perhaps the most important 

 aspect of the controversy is the recognition of the existence of 

 toxins having an action on the leucocytes. A poison causing 

 death of these cells in connection with the pus-forming action of 

 the pyogenic cocci has been described under the name of 

 leucocidin. The investigation of such poisons must be of the 

 highest importance in view of the part played by the blood- 

 cells in the protection of the body against infection, and 

 it is possible that toxins having a fatal effect in strong con- 

 centrations, may, when dilute, be responsible for the phenomena 

 of attraction or repulsion of leucocytes which we know occur 

 round a focus of bacterial growth in the body. 



It is to be noted that in the case of any particular bacterium 

 several different toxins may be at work, and it is also possible 

 that one toxin may have different effects on different tissues 

 of the body. Intracellular toxins of an organism may cause 

 general metabolic disturbances, and its special toxins may act 

 on special tissues. Thus the staphylococcus pyogenes aureus 

 may cause fever, wasting, etc., by its intracellular poisons, a 

 special action on the leucocytes by a leucocidin toxin, and 

 anaemia by its hsemolytic properties. The phenomena of any 

 bacterial disease may thus in reality be due to very different and 

 complex causes. 



The Nature of Toxins. There is still comparatively little 

 known regarding this subject, and it chiefly relates to the extra- 

 cellular toxins. The earlier investigations upon toxins suggested 

 that analogies exist between the modes of bacterial action and what 

 takes place in ordinary gastric digestion, and the idea was worked 

 out for anthrax, diphtheria, tetanus, and ulcerative endocarditis by 

 Sidney Martin. This observer took, not solutions artificially made 

 up with albumoses, 1 but the natural fluids of the body or definite 



1 In the digestion of albumins by the gastric and pancreatic juices the 

 albumoses are a group of bodies formed preliminarily to the production of 

 peptone. Like the latter they differ from the albumins in their not being 

 coagulated by heat, and in being slightly dialysable. They differ from the 

 peptones in being precipitated by dilute acetic acid in presence of much 

 sodium chloride, and also by neutral saturated sulphate of ammonia. Both 

 are precipitated by alcohol. The first albumoses formed in digestion are 

 proto-albumose and hetero-albumose, which differ in the insolubility of the 

 latter in hot and cold water (insolubility and coagulability are quite different 

 properties). They have been called the primary albumoses. By further 

 digestion both pass into the secondary albumose, deutero-albumose, which 

 differs slightly in chemical reactions from the parent bodies, e.g. it cannot be 

 precipitated from watery solutions by saturated sodium chloride unless a 



