234 



I5A0TERIOLOGY 



a 



Grawitz, and the fungus fur floats upon the surface as a 

 thick coating, white above and yellow underneath. 



The fungus of favus (Achorion Schoenleinii). — In the scaly 

 accumulations from persons suffering from 

 favus, Schonlein discovered a fungus to 

 which the name of Achorion Schoenleinii, 

 has been given. The favus crusts or 

 Hcutula show the mycelium of the organ- 

 ism, which is remarkable for the fact that 

 the fibres grow up perpendicularly from 

 the horny layer. The right angle formed 

 by these fibres with the substratum is 

 characteristic of the scutula of favus, since, 

 in the horny scales permeated by iYie fungus 

 of pityriasis versicolor or by the Tricho- 

 phyton the fibres of the organism form 

 acute angles, or run parallel with the cells 

 of the horny layer. 



Unna differentiates three varieties of 

 favus fungus — the Achorion euthythrix, with 

 straight fibres and abundant formation of 

 spores ; the Achorion dicroon, with forking 

 hyphse ; and the Achorion atacton, the hyphs 

 of which run an irregular course and pos- 

 sess peculiar knotty ramifications and many 

 sharp angles. The first forms voluminous 

 greyish-yellow scutula {favus griseus), the 

 second sulphur-yellow scutula, which are 

 slow in developing {favus suljjhurem tar- 

 dus), and the third sulphur-yellow scutula 

 also, which form more quickly {favus sul- 

 ?XG. 88. — stJEFACE phureus celereus). Unna used for cultiva- 



CULTURE OF THE -^ ' '^^w.xuj.yo) 



oramrofimo^sf ta' tion ^ medium composed of 4 per cent, of 



Blood, nine days ^ i, r „j- t f < 



OLD. (After piaut.) agar, 1 per cent, oi peptone, and 5 per cent. 



W 



II. 



