OF THE HUMAN SKIN. 57 



etable life on and in our planet and its inhabitants, 

 have rerealed new worlds of existence to us. 



What, now, are these microscopic germs which 

 plant themselves and groW on and in our skin and 

 its appendages ? The elements of which they are 

 composed may be divided into three morphological 

 formations : 1 . Spores seen under the microscope 

 as round or oblong cells with definite outline ; on 

 tiiese cells, in certain positions, is seen a brownish 

 spot. 2. /Sporidiu, or strings of spores, looking 

 like a rosary. 3. T/iallus fibres, as they are called 

 — that is, long, generally pretty straight, fibres, 

 with double parallel outlines. 



Figure 8 represents these several elements and 

 their mode of development, which is as follows : 

 First, a long thallus fibre increases in length, then 

 we see contractions at several different points, giv- 

 ing it the appearance of a rosary, and finally by 

 further contraction the separate spores are set free. 

 Variety in the relative size and number 6f thesfe 

 separate elements constitutes, most probably, the 

 various differences in the appearances seen in the 

 cutaneous diseases which are caused bj' their pres- 

 ence. These several affections we shall describe 

 in a future chapter, and confine ourselves in this 



