ABSORPTION OF TOXINS. 103 



Certain animal parasites, as the itch mite and skin. 

 jigger, penetrate the surface through mechanical 

 defects of their own making. 



In penetrating wounds, abrasions and transmis- 

 sion by insects the introduction of micro-organisms 

 is a question of mechanical inoculation, or subse- 

 quent growth into the defect. In this case there is 

 no barrier to their entrance into the circulation, 

 until after the appearance of an inflammatory 

 reaction; and if the organism happens to be one 

 which secretes a soluble and easily diffusible toxin 

 (e. g., tetanus bacillus), general intoxication may 

 result even without further dissemination of the 

 living cells. The degree of defect necessary for 

 infection varies with the character and virulence of 

 the organism. The bacilli of plague, anthrax, 

 glanders, and the spirochete of syphilis may enter 

 through lesions which are almost microscopic in 

 size. These organisms possess great infectivity, 

 exceedingly small numbers producing infection. 



Organisms, such as virulent staphylococci, which penetration by 

 reach the hair follicles and sebaceous glands, are 

 able to grow through the succulent epithelium into 

 the surrounding tissues, and to cause a furuncle, 

 carbuncle or cellulitis. This may follow or be 

 accompanied by a primary necrosis of the epi- 

 thelium. Occasionally when furuncles are situated 

 at favorable spots, as near the angle of the mouth 

 or nose, the necrosis may extend to adjacent veins, 

 resulting in a flooding of the circulation with the 

 organisms. 



True soluble toxins are seldom absorbed through 

 the unbroken skin, if we except the case of poison- 

 ing with poison ivy. In Moro's test for tuberculo- 

 sis the tuberculin, incorporated in a paste, is 



