574 A MANUAL OF BACTERIOLOGY 



tinguished from each other clinically and by differences 

 in the parasitic organisms. 



The first variety is an affection of early childhood, 

 forming 80 to 90 per cent, of the ringworms met with in 

 London ; it never attacks the scalp of adults, never 

 affects the beard or nails, is intractable, and frequently 

 epidemic. The parasite is characterised by small round 

 or ovoid spores measuring 3 /x to 4 ju, in diameter. Affected 



FIG. 53. Ringworm in a hair (Microsporon) x 350. 



hairs are generally broken off, forming relatively long 

 stumps, greyish in colour, and possessing a whitish sheath. 

 When suitably prepared in potash this sheath is seen to 

 be composed of the spores agglomerated together without 

 apparent order, and the hairs themselves are filled with 

 delicate parallel mycelial threads (Fig. 53). The fungus is 

 the Microsporon Audouini. Microsporons of this type 

 have been found in the cat, dog and horse. 



The second variety comprises the ringworms with large 

 spores, and is divided into two groups by Sabouraud. 



