120 INFECTION 



in a given case depending largely on the situation of the bite. Most of 

 these poisons exert their effect primarily upon the nervous and vascular 

 systems, besides exhibiting other toxic properties. 



Nature of Venoms. All snake venoms possess a hemolytic power, and 

 venom hemolysis is one of the most interesting of biologic phenomena. 

 Flexner and Noguchi l have distinguished and classified the various 

 elements as hemotoxins, hemagglutinins, neurotoxins, leukotoxins, and 

 endotheliotoxins (hemorrhagin). The endotheliolytic action of the 

 toxins is shown in the glomerular capillaries, where it causes hemorrhage 

 and hematuria (Pearce 2 ). 



Cobra hemotoxin is especially characterized by its power of dissolv- 

 ing the corpuscles of certain species (man, dog, guinea-pig, rabbit) with- 

 out the presence of serum. The explanation of this interesting phenome- 

 non has excited extensive discussion. It is probable that the hemotoxin 

 is in the nature of an amboceptor (Flexner and Noguchi), which is 

 activated, in the absence of serum, by complementing substances (chiefly 

 lecithin) present in the red cells, and in this manner producing hemolysis 

 of these cells. In syphilis the quantity of red-cell lecithin is probably 

 diminished after the primary stage, so that when using definite dilu- 

 tions of venom that are known to hemolyze a certain quantity of normal 

 erythrocytes, an absence of hemolysis of the red corpuscles of a given 

 patient would infer a decrease in complementing lecithin in these cor- 

 puscles and indicate the presence of syphilis. The technic of this reac- 

 tion and its value as a diagnostic procedure will be discussed further on 

 under the head of Venom Hemolysis. 



ENDOTOXINS 



There are a large number of microorganisms, notably the cholera 

 spirillum, the typhoid bacillus, the pneumococcus, and other pyogenic 

 cocci, which, when cultivated and separated from the culture-fluid by 

 filtration, are found to be highly poisonous, whereas the filtrate itself 

 is practically devoid of toxicity except for the soluble hemotoxic sub- 

 stances. In other words, we are dealing with endotoxins, or poisons that 

 are not secreted into the medium in which the bacteria are groiving, but are 

 contained more or less firmly within the bacterial body, from which they 

 are separable by some method of extraction or by autolysis, only after 

 death. 



1 Jour. Exp. Med., 1903, 9, 257; Univ. of Penna. Med. Bull., 1902, 15, 345. 



2 Jour. Exp. Med., 1909, 11, 532. 



