74 VEGETABLE PARASITES 



and there ; which, under the magnifying-glass, 

 prove to be minute rounded, bright-yellow crusts, 

 depressed in the centre, and having one or more 

 hairs passing up through them. These minute 

 yellow crusts gradually and steadily increase in 

 size, till they are about one-fourth of an inch in 

 diameter, and then the edge is elevated above the 

 surface of the skin. It can now be raised from 

 its bed, and, if done with care, a circular depres- 

 sion is seen, corresponding to the convex lower 

 surface of the crust ; this soon fills up, the subcu- 

 taneous tissue having been compressed. A new 

 favus cup, however, shortly makes its appearance 

 again, unless proper means are taken to prevent 

 it. These masses of the fungus may be scattered 

 separately, or if increasing greatly in number, 

 they become thickly set together, touching and en- 

 croaching on each other, thus forming irregular 

 yellowish tubercular masses, rising considerably 

 above the skin, in which the hairs are tangled. 

 For other characteristic symptoms j we have itch- 

 ing, a change in the appearance of the hairs, and a 

 peculiar odor of the crusts . The itching generally 

 attracts attention first, inducing the person to 

 scratch the affected part, and thereby produce 



