There are two main classes of minute microscopical enemies, or disease producing parasites, that infect the human body. ... The skin protects itself to some extent against the harmful effect of these constant visitors, by the manufacture of perspiration and sebaceous material. ... The mucous membrane protects itself against the harmful effect of the parasites in a purely mechanical way just as the skin doesanbsp;...
|Title||:||Brotherhood of Locomotive Firemen and Enginemen's Magazine|