DISEASES OF THE SKIN. 



729 



PcHTwlogyj^-T^Q disease depends upon a cryptoganuc fungus, 

 fiamed the achorion Schonleinii, after Scbonlein, who was the 

 first to suggest that the yellow crusts were constituted by a 

 Tegetable parasite. The primary seat of the parasite is in the 



Fia. 112. 



Fig. 143. 



,lFId^ 142. -^Branches of achorion Scbooleinii in an earlj stage of devel? 

 ,opment, growing from' molecular matter, and mingled with epidermic 

 scales, from a very minute favua crust. 



Fig, 143. — Fragments of the branches more highly developed, with 

 numerous sponilea and molecular matter, from the centre of an advanced 

 favuB crust. — (Bknxett.) 300 diam. 



depth of the hair follicle outside the layer of the epithelium, 

 which covers the root of the hair, and which forms the "innei? 

 toot sheath of KoUiker." — (Aitken.) 



JB^;^^laking their sections of the favois crusts, and treating 



Pio. 144. — Thalli, mycelia, and sporidia of the achorion Sehonleiiuiy 

 Bhowing the mode of reproductioo*— (B£»lfBXT.) 800. diam. 



