346 THE BEGINNINGS OF LIFE. 



abundant mycelium, as where O'idium alhlcans is pro- 

 duced in the affection commonly known by the name 

 of c thrush.' These various organisms exist abundantly 

 enough in almost all the mucous membranes of the 

 body, more especially when there is some unhealthy 

 -mode of action going on in the part; and their preva- 

 lence in these situations is far more dependent upon 

 the presence or absence of such conditions than upon 

 the degree of exposure of the part to the possible con- 

 taminating influence of germs derived from without. 

 Some of those which are least exposed are most prone 

 to throw off the organisms already mentioned, as well 

 as Monads and other more animalized forms '. 



Fungus-germs and rudimentary mycelia are also fre- 

 quently met with upon, and in, the superficial layers of 

 the skin of man and of the lower animals, where they 

 represent the best known characteristics of certain 

 familiar diseases. 



Here again, as in the case of the mucous membranes 

 and of the general parasitic diseases, there is the possi- 

 bility that such growths may be occasioned by actual 

 contact with some disseminated and all-pervading 

 Fungus-germs. We know, indeed, that these parasitic 

 diseases are contagious; that persons free from such 

 maladies may become affected, provided the infecting 



1 See Dr. Gros on Vaginal Animalcules, in ' Bull, de la Soc. de 

 Nat. de Moscou,' 1845, p. 426; and Mr. T. R. Lewis in his previously 

 quoted ' Report,' as to forms which may be met with in the intestinal 

 canal. 



