CUTANEOUS INFECTIONS. 95 



meningitis and is present in the blood in virtually 

 all cases of pneumonia. The gonococcus, aside 

 from its predilection for the urethra, readily 

 becomes localized in the joints, and occasionally on 

 the valves of the heart. The micro-organism which 

 causes acute articular rheumatism has a specific 

 affinity for the joints and endocardium. It would 

 seem that the virus of hydrophobia attacks the cen- 

 tral nervous system almost to the exclusion of 

 other tissues. The spirochete of syphilis, although 

 it may cause changes in any organ of the body, is 

 particularly prone to produce proliferation of the 

 vascular endothelium and subendothelial connect- 

 ive tissue. 



The fungi which cause pityriasis versicolor. Cutaneous 



, , ., , Infections. 



ringworm, barber's itch, erythrasma and favus 

 attack only the cutaneous surfaces. Eingworm in 

 the child is prone to be limited to the scalp, whereas 

 in the adult it occurs more commonly on the 

 smooth skin. In ringworm and pityriasis versi- 

 color only the superficial skin is involved, and in skin. 

 the former the hair follicles and the hairs. In 

 favus and barber's itch the cutis vera is often 

 invaded, and in the former healing usually takes 

 place with scar formation. The organisms appar- 

 ently never become generally distributed in the 

 body, and never, or rarely, cause symptoms of gen- 

 eral intoxication. 



There are many other organisms of more general 

 pathogenic powers which frequently cause infec- 

 tions in the skin and other superficial tissues, 

 although they have no specific relationship to the 

 skin. They are found now in one tissue and now 

 in another, and may in fact invade any organ of 

 the body. Such organisms are the streptococci 



