ALCOHOLIC FERMENTS. 195 



SACCHAROMYCES APICULATUS. KEESS. 

 (Fig. 53.) 



As already pointed out, the name of this ferment is 

 incorrect according to our present views, for only those 

 budding-fungi which yield endogenous spores are considered 

 to belong to the Saccharomycetes, and the fungus in question 

 does not possess this property. We will, however, provisionally 

 retain the old generic name, as has been done by Hansen, 

 until the systematic classification has been further developed. 



As is known, this ferment was the subject of one of the 

 finest and most thorough biological investigations of our 

 time, for Hansen was enabled, after several years' work, to 

 determine both its habitat in nature and its regular migra- 

 tions at the different seasons of the year. The reason that 

 this species was selected for the investigation was that, whilst 

 other species occur in very varied and uncertain forms, which 

 makes the study of their occurrence in different localities 

 very difficult, this ferment can be recognised with certainty 

 by its form, since it always occurs in cultures with lemon- 

 shaped cells ; this is the typical form of the species. 



Sacch. apiculatus occurs abundantly in wine-yeast, 

 especially during the first stages of the fermentation, also in 

 Belgian spontaneously-fermented beer ; in nature it is found 

 abundantly on ripe, sweet, succulent fruits. 



If a little of such a growth in a drop of nutritive liquid 

 is examined under the microscope, the development of the 

 fungus can be followed. This is, as was first pointed out by 

 Hansen, very characteristic (compare Fig. 53). It is seen 

 that the buds formed from the typical lemon-shaped cells 

 may be either lemon-shaped (a, 6, c, e, /) or oval (a c) ; 

 it is also noticed that the oval cells must first form one or 

 more buds before they are able to assume the lemon-shape 

 (e -/), and finally, that the lemon-shape of a cell attained 

 by budding (&, k', k") may be lost again on the formation 

 of a new bud (&'"). Under other conditions the cells can 



