64 VEGETABLE PARASITES 



ance, as well as simulating the products of true 

 disease of the skin. It will be seen, therefore, 

 that it is not only extremely interesting, but abso- 

 lutely necessary for the physician to be thoroughly 

 acquainted with the natural history of these veget- 

 able parasites, so that he may be able to detect them 

 when on the skin, or its appendages, the hair and^ 

 nails. He must also be acquainted with all their 

 phases of development, and the appearances their 

 presence produces, and thus be able to distinguish 

 the effects they cause from similar ones, the result 

 of, so to speak, true diseases. Fortunately the 

 more extended use of the microscope by medical 

 practitioners places this recognition more and 

 more in their power. It is our object here, how- 

 ever, to let the laiti/ know of their existence, and 

 the consequences of their continued growth on the 

 surface of our bodies. 



These vegetable spores are microscopic objects, 

 varying in size, being some thousanths of an inch. 

 As we said, their smallness enables them to pen- 

 etrate every natural cavity, such as the folds in 

 the skin ; and the}?- are carried everywhere by the 

 wind where dust can get. Their form is generally 

 oval or spherical. They are very firm, so as to be 



