4 io MYCODERMA. 



constantly following the development of individual cells into 

 chaplets, convinced himself of the morphological variability of 

 the cells. 



This phenomenon has been observed by different workers at 

 various times. WINOGHADSKY (XI.) attributes the variation, not 

 merely to the specific nutrient medium, but more particularly 

 to the greater or smaller supply of oxygen available for the grow- 

 ing vegetation. Thus, one and the same species will produce 

 cells similar to those of yeast when oxygen is present, whereas, 

 in the absence of that element the growth is mycelial in character. 

 It was also found by WILL (XIII.) that the form of the Myco- 

 derma species examined by him varied between wide limits, as did 

 also the dimensions and contents of the cells ; and MEISSNER (XI.) 



FIG. 190. FIG. 191. FIG. 192. 



Mycoderma from Eltville Mycoderma from bilberry Mycoderma from KUde- 



red wine. Pastorianous wine (West Prussia). sheimer wine, 



and round cell forms. Pastorianous cell forms. Irregular cell forms. 



Magn. 600. Magn. 600. Magn. 600. 



arrived at a similar result. In the races subjected to mopho- 

 logical examination by him, the largest cells measured 4.6 p, by 

 19.2 fij those of the other races remaining below this level. 

 According to WILL (XIII.), the typical Mycoderma cells measure 

 8-1 1 p in length (the mean being 9 p], and 5 p in breadth. 



The cell form is pastorianous, with rounded edges (Figs. 190 

 and 191), though, as pointed out by P. LINDNER (XXXI.) irregular 

 half-moon and pear-shaped cells (Fig. 192) are also found now 

 and then. WILL (XIII.) gives precise data respecting the integu- 

 ment and contents of the cells. According to this worker, the 

 young cells exhibit only faint refraction after their contents have 

 been shrunk by the action of glycerin. The membrane is usually 

 thinner than in yeast cells ; and even in the slender cells, occur- 

 ring regularly in older cultures, the integument is pale and seems 

 to remain so always. On the other hand, pace WILL (XI II.), 

 the slightly oval, tough cells, appearing in older cultures, are dis- 

 tinguishable from the other cells by their strong membrane, 

 bounded by a broad outline. Treatment with i per cent, osmic 



