SACCHAROMYCES. 315- 



.) 



of the mould in and upon sterile substrata nothing but 

 a growth of Schizosaccharomyces is obtained, and no- 

 mycelium.* 



In all three cases such substrata were utilised as had 

 otherwise proved favourable for the growth of moulds. But 

 it was impossible, under laboratory conditions, to reproduce 

 the natural conditions which favour the formation of these- 

 Dematium, Monilia, and Oidium-Uke fungi. 



Further investigation will determine how far such condi- 

 tions are to be found in nature. These observations, at any 

 rate, show that there are cases where the natural conditions 

 allow of a development which cannot be substantiated by 

 artificial conditions in the laboratory, and the conclusion 

 appears to be warranted that other fungi, including higher 

 fungi, may behave in the same way, like the Ustilaginece and 

 other forms which regularly reproduce budding growths, which 

 are incapable of forming endospores. An excellent but isolated 

 example of the development of Saccharomyces cells from a 

 fungus, Glososporium, belonging to a higher system, has been 

 recorded by Vialla and Pacottet.f 



The basis of a scientific system of classification was suggested! 

 by Hansen in 1904 as follows : 



Family Saccharomycetes. 



Budding fungi with endospores and vigorous formation of 

 yeast cells. Typical mycelium only occurs in few cases. 

 Every cell may occur as the mother-cell of a spore. Spores- 

 unicellular. Number of spores in each mother-cell usually 

 from one to four, seldom, up to twelve. 



* As stated in the section on Variation, Lepeschkin observed a similar weak 

 formation of mycelium in individual cells of S. mellacei. 



f Whatever may be the much-discussed genetic connection between Asper- 

 gillua Oryzce and Saccharomyces, it is certain that the conidia of many individuals 

 have been observed to bud. How far a mistake may have occurred in transferring: 

 these budding growths to gypsum blocks, where they showed endogenous spore- 

 formation, it is no longer possible to say. All subsequent experiments with growth* 

 of Aspergillus species have given negative results. 



