ALCOHOLIC FERMENTS. 131 



(Fig. 31, see also description of the species), is distinguished 

 from the last-mentioned in that the spores are of a quite 

 different shape, and resemble the spores of Endomyces 

 decipiens. 1 They somewhat resemble a half sphere with a 

 rim round the base 



During germination the spore swells and the projecting 

 rim can either remain or disappear. Buds then make their 

 appearance at different points on the surface of the spore. 



One of the objects of Hansen's investigations was also to 

 determine in what way the formation of spores was influenced 

 by different temperatures, with the view to ascertain whether 

 the different species behave alike, or whether it might not be 

 possible in this way to discover different characteristics. It 

 was, therefore, necessary to determine : 1, the limits of 

 temperature, i.e., the highest and lowest temperatures at 

 which spores could be formed ; 2, the most favourable tem- 

 perature, i.e., the temperature at which spores appeared in 

 the shortest time ; and, finally, 3, the relation of the inter- 

 mediate temperatures. 



In determining the desired intervals of time, the moment 

 was registered at which the cells showed distinct indications 

 of the formation of spores (compare Figs. 26 and 32). It is 

 not possible to make use of ripe spores in these determina- 

 tions, since no criterion exists for complete ripeness. 



The results obtained by Hansen are as follows : 



The formation of spores takes place slowly at low tem- 

 peratures, more rapidly as the temperature is raised to a 

 certain point ; when this point is passed their development 

 is again retarded, until finally a temperature is reached at 

 which it ceases altogether. 



The lowest limit of temperature for the six species first 

 investigated was found to be O5 to 3 C., and the highest 

 limit 37-5 C. Hansen also determined the intermediate 

 temperature and time relations for these six species, and 



1 A fungus which is parasitic on the lamellae of certain mushrooms. 



