144 VEGETABLE PAKASITES. 



Unfortunately, we know little or nothing of the state of the 

 fluids, whether in all, or only in some who are scrofulous and the 

 like, they are favorable to the development of the parasites. Tinea 

 tonsurans is sometimes primary, and sometimes follows herpes 

 circinatus, and seizes at once on^ or several parts of the head 

 covered with hair, usually the back of the head first, but also 

 other parts of it. If the disease succeeds herpes, it manifests 

 itself at first in the centre of the herpetic rings, where a small 

 tuft of hair becomes paler, reddish, and lighter than the neigh- 

 bouring hair, and the skin below it a little embossed and covered 

 with epidermic scales, from whence the disease spreads rapidly 

 over the adjoining hair, and forms patches of 1 2 centimetres 

 in diameter. Here and there may be seen among the broken 

 hair of these spots some uninjured hairs. The diseased places 

 are, moreover, covered with spots of white scales, which have a 

 velvet-like appearance, and form sheaths round the broken hairs. 

 Gradually these isolated patches, which represent irregular or 

 circular plains, deprived of their hair, run together into one. 

 If the broken hairs of such a patch are seized with a pair of 

 pincers, they break off with great facility quite close to their 

 point of insertion. Generally this tinea is less frequently fol- 

 lowed by lasting alopecia than ihefavus. 



Bazin thinks he has found this fungus also on animals. He 

 mentions a gens-d'arme who had herpetic patches on the 

 palmary surface of the right fore-part of the arm, one of which 

 had lost its hairs, and for which the man could only account by 

 having been infected with tetters, together with five or six 

 comrades, whilst cleaning horses which were infected with the 

 disease ; which statement Bazin found to be true on examining 

 the horses. He found, indeed, that the hair was broken off in 

 these places; and, moreover, as in herpes tonsurans, a whitish, 

 squamose, scaly secretion perforated with hair. Deffis and Bazin 

 found under the microscope a formation analogous to the above- 

 mentioned fungus, with the exception that the spores and tubes 

 were much smaller. 



These microscopic discoveries explain not only the perti- 

 nacity of the disease, since it is well known that the lowest 

 plants develop themselves most intensely and rapidly in a 

 favorable medium, but also its contagious character which 

 is no longer doubtful. The fungus itself is the sole cause of 

 these changes of the hair and of the secondary irritation and con- 



