RINGWORM 



"5 



Other varieties of ringworm sometimes do not : the latter persist more 

 frequently, though even they are rare in the adult. It is very rare 

 in adults, and it rarely attacks regions other than the head. Nearly 

 all microsporon infection is human in origin, but there is also a 

 microsporon of the dog and cat distinguishable in culture {Micro- 

 sporon canis vel lanosum) which usually affects the glabrous skin 

 more abundantly than does Aiidouini and is not infrequently 

 slightly inflammatory on the scalp. 



The most important clinical fact about the M. Aiidouini is that 

 ringworm caused by it is extremely intractable, and may run a 

 prolonged course in spite of the most skilful treatment other than 

 the X rays. 



Fig. 25. — Microsporon Acdouini. 



The Trichophyton (or Megalosporon) endothrix attacks the interior 

 of the hairs, and forms long chains ; it always involves the hair 

 just inside the cuticle. Its spores are somewhat larger than those 

 of the preceding species, but the difference is not great ; the 

 organism is most easily recognized by the chain-like arrangement 

 , of its spores, and by the fact that they lie within the hair, the 

 cuticle of which usually remains intact (Plate VI., Fig. 2). 



This fungus is a rare cause (in this country) of ringworm of the 

 scalp, and the disease caused by it appears to be somewhat easier 

 to cure than that due to the microsporon, though opinions on this 

 point are divided. It also attacks other regions of the body, 

 causing tinea circinata. It is not infrequently the cause of beard 

 ringworm, and is commonest in ringworm of the nails. 



It is usually derived from a human case. Two species of 



* Fig. 25 is from Curtis's "Essentials of Bacteriology " (Longmans). 



