OF THE HUMAN SKIN. 71 



idea of the vegetable parasitic growths, and the 

 morbid or unnatural appearances they produce on 

 the surface of our bodies. Perhaps the best plan 

 will be to take up in turn each disease, as there 

 are not many, describe what it looks like, what it 

 simulates, what its consequences are, and what 

 can be done for cure by its unfortunate possessor, 

 or that possessor's parents or attendants ; in other 

 words, to give a medical history, as little techni- 

 cal as possible, and as clearly and concisely ex- 

 pressed as the subject will allow of. 



It must be remembered that these vegetable 

 parasitic diseases we are about to describe, are 

 not new affections recently appearing in the world, 

 but are probably as old as man himself. Veg- 

 etable* moulds existed before man's advent on our 

 globe ; and when he appeared, they attacked and 

 developed on his skin, as on that of other animals. 

 As far back as any medical writings extend, we 

 can trace the descriptions of diseases which we 

 now readily place in the list of those due to the 

 presence of a vegetable mould. It was not till 

 about 1842, that the physician's inseparable com- 

 panion, the microscope, brought to light the cause 

 of these several cutaneous troubles, and showed 



