38 THE MICROSCOPE. 



first indicated its presence in connection with Herpes Tonsurans 

 and Mentagra in two memoirs read before the Academy of Science 

 of Paris, but the first thorough description was given by Malmsten, 

 a Swede. This fungus Hke the Achorion Schoenleinii consists of 

 spores and mycelium. The spores are mostly round and much 

 smaller than those of the achorion, and the mycelium is not 

 usually as abundant nor as luxuriant. The favorite, in fact, special 

 seat of the growth is in the hairs and hair follicles, and to a very 

 slight extent among the epidermic cells of the surface. The five 

 varieties of Trichophytosis present certain common features. They 

 are all contagious, and may be transmitted from one person to an- 

 other, from man to certain animals, and from certain animals to man. 

 A given variety may produce its like, or on the other hand, either of 

 the other varieties, and several varieties may co-exist upon the same 

 person. The trichophyton never gives rise to Favus, nor the 

 Achorion Schoenleinii to Trichophytosis, I have called attention to 

 these parasites Achorion Schoenleinii — Microsporon Furfur 

 Tricophoton distinct species as illustrating the value of the Mi- 

 croscope as an instrument of precision. 



c 



COMMERCIAL FIBRES. 



BY LOUISA REED STOWELL. 



OTTON consists of the down or fine cellular hairs attached to the 

 seeds of plants belonging to the germs Gossypiuin and to the 

 natural order Malvaccic. It is indigenous to all of the intertropical 

 regions. These plants supply the raw material for one of our great- 

 est industeries, and for the clothing of all nations, and certainly may 

 claim a recognition among the most valuable of nature's production. 

 The cotton plants cultivuted in the new and in the old world 

 constitute the two great divisions in the commercial cottons and are 

 known as the Oriental and the Occidental, or the Indian and the 

 American cottons. The seeds of the Indian cotton are never black 

 and are always covered more or less with epidermal hairs, and the 

 curvature at the base of the leaf lobes is compounded of two op- 

 posite curves, and not purely heart-shaped as in the case of the Am- 

 erican plant. " The cottons most in demand among manufacturers of 

 the world, are those of America. The Sea Island plant in tn^ soft 



