CHANNELS OF INFECTION 2 1 



that physicians run the greatest danger of accidental 

 infection. 



The question whether infection may occur through 

 the unbroken skin has been studied and an affirma- 

 tive result obtained. The liability to infection in this 

 way is, however, comparatively slight. When it does 

 occur, it appears that the germs penetrate through 

 the hair follicles. Infection may occur through mu- 

 coiis membranes, and it is in this way that infectious 

 conjunctivitis and various other specific inflamma- 

 tions of mucous membranes are propagated. Infec- 

 tious skin diseases, such as scabies (itch), ringworm, 

 barber's itch, etc., may, no doubt, be contracted by 

 susceptible persons, when conditions are favourable, 

 independently of any wound or abrasion, especially 

 in those who do not indulge in frequent bathing and 

 thus give the germs time to penetrate the epidermis. 



Researches made during the past few years have 

 demonstrated that malarial fevers and yellow fever 

 are communicated to man through the bites of in- 

 fected mosquitoes. Certain infectious diseases of lower 

 animals are also transmitted by insects. Thus it has 

 been shown that ticks are responsible for the propa- 

 gation of a fatal disease of cattle known as Texas 

 fever, and an infectious disease of horses, which has 

 recently prevailed extensively in the Philippine 

 Islands, is communicated by a biting fly, which 



