OF THE HUMAN SKIN. 31 



mates fruitlessly got rid of, as contagion soon 

 caused them to become as Infested as before. 

 There was, however, great ignorance as well as 

 great neglect. Even in times of peace, the sur- 

 gical staff of our prisons, institutions of correc- 

 tion, school-ships, asylums, children's homes, 

 etc., know only too well how hard it is to enforce 

 a personal cleanliness, which shall prevent the 

 presence of contagious vermin. With great ar- 

 mies in the field it is impossible ; but not neces- 

 sary with these in times of peace. 



We do not propose to speak here of the vari- 

 ous insects which attack man by stinging, or 

 those which draw blood from the skin for food, as 

 they cannot be strictly called parasites. We 

 mean of the former class, scorpions, ants, spiders, 

 etc., and of the latter class, bed-bugs, fleas, mos- 

 quitoes, gnats, many species of flies, etc. 



We will, therefore, now pass to the considera- 

 tion of some of the animal parasites which live 

 in the skin, or which may, under certain circum- 

 stances, deposit their eggs there. The great 

 blue-bottle fly, musca vomitoria, lays its eggs in 

 the orifices of the human body, or in wounds and 

 ulcers. The removal of their larvae is a matter 



