YEASTS AND TORUL^E. 137 



ramifications of branches given off by the central coiled 

 hypha. Inside each ascus eight ascospores are produced. 

 Ultimately all the structures lying within the perithecium, 

 save the spores, undergo disintegration, so that the mature 

 perithecium consists of a small hollow sphere within which 

 lie the loose spores. These latter are ultimately freed by 

 the decay of the wall of the perithecium and develop into 

 new individuals. The commonest method of reproduction 

 is by the formation of spores (gonidia or conidia), which 

 are clearly of non-sexual origin. These are formed exter- 

 nally in the hyphae and not inside sporangia. A filament 

 grows out, and at its termination a club-shaped swelling is 

 formed on which a series of flask-shaped cells, called sterig- 

 mata (vide Fig. 44 C6), are perched. At the free end of 

 each of these, an oval body, the spore or gonidium is 

 formed, and this becoming free, can give rise to a new 

 individual. 



(2) Penicillium Glaucum. This is perhaps the most 

 common of all the fungi met with in bacteriological work. 

 It is the common green cheese mould, and its spores are 

 practically omnipresent. The mycelium is like that of the 

 aspergillus. Perithecium formation takes place, but the 

 commonest mode of reproduction is by gonidia (vide Fig. 

 44 D). A filament (called a gonidiophore) grows out, 

 and at its end breaks up into a number of finger-like 

 branches. On the point of each of these a flask-shaped 

 sterigma is developed. On the end of this a row of oval 

 spores appears. These break off, and can give rise to new 

 individuals. 



Yeasts and Torulse : Saccharomyces, Torula, Myco- 

 derma. These are of the greatest importance, of course, 

 in brewing and baking. They only concern us as being of 

 not uncommon occurrence in the air. They consist of 

 round or oval cells usually many times larger than bacteria. 

 They often reproduce themselves by budding (vide Fig. 

 44 E, F), a portion of the cell protruding, and finally 

 being cut off to form a new individual. Endogenous 

 spore formation also occurs (vide Fig. 44 G). Many of the 



