172 AIDS TO BACTERIOLOGY 



Microsporon Audouini is met with in young children. 

 Sequeira (School Hygiene, August, 1912) found it present 

 in 89 -8 per cent, of ringworms in children. Hewlett says 

 that it never attacks the scalp of adults, never affects 

 the beard or nails, is very intractable, and frequently 

 epidemic. It occurs as a whitish sheath round the stumps 

 of broken hairs. Microscopically the parasite appears as 

 round or ovoid spores measuring 3 JUL to 4 jbt, in diameter. 



The second form comprises two varieties. In one, 

 which is exclusively of human origin, the spores are met 

 with chiefly in the interior of the hairs, and hence is 

 termed the endothrix variety. It occurs in late childhood 

 (10-2 per cent, of children's ringworms [Sequeira]). In 

 the ectothrix variety, which principally affects the beard 

 and nails, and is derived from animals, the spores lie on 

 the exterior of the hairs. In both the spores are large, 

 measuring 4 /u, to 12 /j, in diameter, and the parasite is 

 known as the Trichophyton megalosporon endothrix and 

 ectothrix respectively. 



The fungi can be readily cultivated on all the ordinary 

 media, but beer- wort gelatin and agar are to be preferred, 

 and the best of all is a maltose agar (Blaxall's English 

 Proof Agar), composed of peptone 1 gramme, maltose 

 4 grammes, agar 1;3 grammes, and water 100 c.c. The 

 growths are white and fluffy, and rapidly liquefy gelatin, 

 the different varieties showing certain differences, and 

 microscopically they consist of a tangled mycelium, 

 with spores. 



A pure culture may be often obtained by chopping up 

 an affected hair and strewing it over an agar plate. 

 After incubating for three to seven days at 24 or 30 C., 

 colonies appear as little, fluffy, whitish spots. To 

 diagnose a case of ringworm, it is generally sufficient to 

 examine one of the suspected hairs under a low power 

 ( inch), when it will be found to be covered with spores. 

 To facilitate examination, the hair may first be soaked 

 in alcohol and ether and then in 10 per cent, caustic 

 potash solution. If the patch itself is examined, spores 

 will be found on the surface, while a little below will be 

 seen a matted mass of mycelial branching. The organism 

 may be stained with fuchsin or by Gram's method, and 

 permanent preparations (unstained) may be mounted 

 in glycerin jelly. 



