12 MORPHOLOGY AND DEVELOPMENT OF YEASTS 



In the latter case, they are able to turn about and, remaining 



attached, undergo a transverse division 

 as with Sch. octosporus. They often re- 

 main completely adherent to form a 

 chain with 2, 3, or 4 elements. Under 

 certain conditions, notably in an en- 

 vironment with too little air, the cells 

 show a very marked tendency of adhering 

 together in chains which branch. 



Sulc 1 has proven the existence in 



Fig~lO.- Doable Cells. The certain ^Uzosaccharomyces of certain 

 Membraneous Layer is Partly fatty bodies. These Schizosaccharomyces 

 (aC " muM Ply indifferently by partition or 

 budding. This should be confirmed. 



Durable Cells 



In the pellicle which appears after a period of time on the surface 

 of nutrient media, and in deposits at the bottom of flasks containing 

 certain special media (sugar 

 solutions containing tartaric 

 acid or citric acid and mineral 

 matter), Will 2 has observed 

 cells which possess thick walls 

 and whose contents are rich 

 in glycogen and fats. 



From the researches of 

 Will and Casagrandi, 3 these 

 cells possess a double mem- 

 brane; the outer one is very 

 fragile and easily broken to 

 pieces. These membranes are 

 made more visible by treating 

 the cell with osmic acid or by 

 the Ripart-Petit fluid (hydro- 

 chloric and chromic acids, 1 

 per cent). 



Will has called these cells 



11. Germination of Durable Cells 

 (according to Will). 



1 Sulc, K. "Pseudovitellius" und ahnliche Gewebe der Homopteren sind 

 Wohnstatten symbiotischer Saccharomyceten (Sitzungsberichte der Konigl. Bohm. 

 Gesellschaft der Wissenschaften in Prag. March 30, 1910). 



2 Will, H. Vergleichende Untersuchungen an vier untergarigen Arten von 

 Bierhefe. Zeitschr. f. d. ges. Brauwesen, Munich, II, 18, 1895. 



3 Casagrandi. 1897. Ueber Morphologic der Blastomyceten. Cent. Bakt., 3. 



