190 MICRO-ORGANISMS AND DISEASE [CHAP. 



in a linear manner, or as a group if the gemmation takes 

 place laterally. 



Under varying conditions of growth, e.g. on transplanting 

 ordinary yeast growing in sugar-containing fluids on to potato, 

 but sometimes also in the same nutritive fluid, it is observed 

 that some of the yeast cells enlarge twice, thrice, and more 

 times ; they then form in their interior two, three, or more 

 small cells by endogenous formation ; these new cells are 



FIG. 112. TORULA, OR SACCHAROMYCES. 



In the lower part of the figure an ascospore and four isolated spores (after Rees) 



are shown. 

 Magnifying power about 700. 



regarded as spores 1 the mother-cell being an ascospore 

 and become free by finally bursting the membrane 

 of the mother-cell. On sowing these new cells into 

 sugar-containing fluids they multiply by the process of 

 gemmation. 



Classifying them according to physiological function there 

 are various species of torula or saccharomyces. They all 



1 T. de Seynes, Comptes Rendus, 1866; Rees, Bot. Zeitschr. 1869; 

 Hansen, Carlsberg Laborat. 1883. 



