362 



FUNGI RELATED TO THE YEASTS 



with the mycelium -reduced to its simplest form. In other media 

 the filaments are most common. Cultures on slices of carrot have 

 quite a development of mycelium while in Raulin's solution growth is 

 almost solely of the yeast-like structures. According to Roux and 

 Linossier, 1 the yeast structure is the normal one while the mycelial 

 form appears only under conditions which reduce the vitality. Ac- 

 cording to Vuillemin, on the contrary, the filamentous form is the one 

 which is normal and the yeast-like form appears only under bad condi- 

 tions of food supply. The yeast-like struc- 

 tures are spherical, oval or elongated, and of 

 variable dimensions. On Raulin's solution 

 they become rather large and appear as large 

 spherical cells somewhat resembling those of 

 S. cerevisiae (Raj at 2 ). Guilliermond has 

 shown that the units of the filaments contain 

 ordinarily a single nucleus, rarely more, and 

 the yeasts are always uni-nuclear. This has 

 been confirmed by H. Penau. 3 



Roux and Linossier, and later Vuillemin, 

 have established in old cultures the production 

 of very resistant forms comparable to chlamy- 

 dospores. These, which have received the 

 name of chr6nispores or chlamydospores, de- 

 velop at the end of certain filaments in the 

 form of distended cells filled with glycogen and 

 surrounded with a thick membrane with three 

 superimposed layers (Fig. 152, 4). Changed to different media, these 

 chlamydospores germinate and produce yeasts or filaments. 



Vuillemin has described, on the other hand, internal globules, 

 (Fig. 155, 3) absolutely analogous in appearance to yeasts, which form 

 on the interior of the filaments. The author considers them as re- 

 sistant forms. 



In our opinion, these internal bodies may be similar to those which 

 are commonly found among the fungi. There are, here and there, the 

 formation of yeasts or conidial forms, in the interior of an inter- 

 calary unit, with degenerating contents, by the budding of a contiguous 

 unit. This latter buds in the interior of a dead unit which is near 



1 Roux, G., and Linossier, G. Rech. morph. sur le champ, du Muguet. Arch, 

 de Med. experim. 1890. 



2 Rajat, H., Le champ, du Muguet. These de doct. en medecine, Lyon, 1906. 



3 Penau, H., Cytologie de L'End. albicans forme levure, v. CLII, 1900, and 

 Cytologie de TEnd. albicans forme mycelienne. C. R. Ac. des Sciences, v. CLII, 

 1910. 



Fig. 155. Yeast Forma 

 from a Case of Thrush. 



2, Mycelial Forms from a Case 

 of Thrush; 3, Internal Glob- 

 ules; 4, Chronispores; 5, Asca 

 (after Vuillemin). 



