LOCATION OF INFECTIVE ORGANISMS 245 



SPECIFICITY OF LOCATION OF INFECTIVE ORGANISMS. 



It is readily apparent that certain disease organisms tend 

 to locate themselves in definite regions and the question 

 arises, Is this due to any specific relationship between organ- 

 ism and tissue or not? Diphtheria in man usually attacks 

 the tonsils first, gonorrhea and syphilis the external geni- 

 tals, tuberculosis the lung, "choleras" the small intestine, 

 ''dysenteries" the large intestine, influenza the lungs. In 

 these cases the explanation is probably that the points 

 attacked are the places where the organism is most commonly 

 carried, with no specific relationship, since all of these organ- 

 isms (Asiatic cholera excepted) also produce lesions in other 

 parts of the body tvhen they reach them. On the other hand, 

 the virus of hydrophobia attacks nerve cells, leprosy fre- 

 quently singles out nerves, glanders bacilli introduced into 

 the abdominal cavity of a young male guinea-pig cause an 

 inflammation of the testicle, malarial parasites and piro- 

 plasms attack the red blood corpuscles, etc. In fact, most 

 yathogenic protozoa are specific in their localization either 

 in certain tissue cells or in the blood or lymph. In these 

 cases there is apparently a real chemical relationship, as 

 there is also between the toxins of bacteria and certain tissue 

 cells (tetanus toxin and nerve cells). Whether "chemo- 

 therapy" will ever profit from a knowledge of such chemical 

 relationship remains to be developed. It appears that a 

 search for these specific chemical substances with the object 

 of combining poisons with them so that the organisms might 

 in this way be destroyed would be a profitable line of 

 research. 



