ACHOIIION SCHOENLEINII. 167 



very marked edges, 0-003 6 ram. "broad, and 0*007 10 nim. long, 

 not changed in water or vinegar ; homogeneous in their interior, 

 transparent, and refracting the light strongly, and are found, 

 on closer examination, to be filled in their centre with a very 

 fine powder of molecular granules, and exhibiting, on the addition 

 of water, a molecular motion of the spores (Lebert, Reruak). 

 Some of the largest round spores show a small granulation of 

 O'OOl 2 mm., and the longest the same at each end. There 

 are, likewise, ovoid, almost four-sided spores, triangular and 

 rounded off at the corners, which are swollen at the ends and 

 contracted in the middle, spherical and longish, and grouped 

 together, forming a simple or sometimes a fork-like divided row 

 of from four to twelve spores. Sometimes only spores of the 

 same size are grouped together, sometimes of different sizes, and 

 sometimes the ramified tubes are found to communicate amongst 

 themselves. This fungus should be examined with a power of 

 from 500 to 600 diameters. 



Seat of the favi. They are principally found on the head, 

 covered with hair, but also on all other parts of the body ; on the 

 face, the shoulder-blades, the external ear, on the front of the 

 thighs, the penis, and the testicles, and not merely on those parts 

 of the skin covered with hair. At first a reddened spot on the 

 skin, with a yellow dot in the centre, is perceived. If this spot 

 is opened, a drop of matter is sometimes seen to exude, some- 

 times not ; and below lies the readily formed mass of fungi as a 

 yellow knot. The favi are imbedded in the skin, which is de- 

 pressed and thinned by them ; their surface is firmly attached, by 

 immediate contact, to the depressed part, which is deeper in the 

 skin of the remaining part of the body than on the head. As 

 soon as the mass of fungi becomes exposed to the air, after 

 the loosening of the epidermis, a scab is deposited, sometimes 

 with and sometimes without pus, and the external edges still 

 covered with epidermis, which must be cut off if the scab is to 

 be detached. When the scab is quite dry, this operation rarely 

 succeeds completely. Broad crusts of 1" diameter and more 

 are formed by continued exudation. The opening of the canal 

 of the hair is, therefore, no necessary seat of the favi, but 

 becomes so in the course of its spreading ; in small favi, 

 from 3 4 mm. diameter, they are seen to be pierced by 

 four or five hairs. The adipose tissue has been erroneously 

 thought to be their seat, and they were even regarded as hyper- 



