SACCHAROMYCES. 369 



An asporogenous variety has been developed by Hansen 

 by cultivation at a temperature lying between the maximum 

 for spore-formation and the maximum for budding. When 

 S. anomalus is cultivated near the limiting temperature for 

 budding, it grows only as sedimentary yeast. The tempera- 

 ture limits for budding in wort are 37 to 38 C. and 1 to 0-5 C. 



According to Will, the walls of the young cells are coloured 

 black with 1 per cent, of osmic acid. This, however, does not 

 occur if the cells have previously been treated with alcohol. 

 Many of the cells enclose large oil drops, which especially occur 

 in cells derived from gypsum blocks that do not yield spores. 



Spores are developed on various substrata, both liquid and 

 solid, even when abundant nutriment is present. 



The form of the spores is highly characteristic (Fig. 78) ; 

 it resembles a hemisphere with a 

 projecting rim round the base. 

 On germination the spores swell 

 and develop buds (see Fig. 57). 



The maximum temperature 



for Spore-formation is 32-5 tO Fi. IS. -Spores of Saccharomyce.it anomalus 



34 C. ; the minimum tempera- { S^SSS^rS^S^& 

 ture 3 to 6 C. ; the optimum n e SnSffiS*S tffbST^S 

 is 30 C. (17 to 19 hours). 

 (Nielsen.) 



After Hansen had drawn attention to this curious Sac- 

 charomyces species, this or similar species were observed by 

 many workers. Thus, for instance, Meissner undertook a very 

 comprehensive morphological and physiological investigation 

 of three different species from Johannisberg must, from beer, 

 and from samples of New Zealand soil. He described 

 the form of the cells (in two cases round and in the third 

 very elongated), the appearance of the films, the fermented 

 liquors, and the giant colonies. The pale yellow must passes 

 gradually into a dark brown, and the liquid gives an alkaline 

 reaction. Both formation and decomposition of acid takes 

 place. Reference may be made to Meissner's work on species 

 of Mycoderma vini carried out at the same time. 



Steuber described four different kinds of S. anomalus, three 

 of which produce acetic ether, whilst he states that one produces 



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