MOULDS 



199 



These moulds enter by wounds, cracks, or hair fol- 

 licles, and develop in the superficial layers of the skin. 

 The mechanical irritation set up by their presence is 

 largely responsible for the various diseases they 

 occasion. To be sure, they can form enzymes, but of 

 what importance they are in human lesions is not 

 known. The diseases are not highly contagious, but 



FIG. 57. Achorion Schonleinii. (Fliigge.) 



of great tenacity when once well advanced. Infective 

 material comes away in all cases with discharges, and 

 should be burned. Their principal diseases in the 

 human being are as follows: 



Ringworm. Of this there are two varieties ring- 

 worm of the skin, Tinea circinata, and ringworm of the 



