472 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. i£6.— Tokul.\, or Saccharo^iyces. 



In the lower p.irt of the llgiire :in asco^poie and four isolated spores (after Rces) 



are .shown. 



Magnifying power about 700. 



regarded as spores ^ — 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 



^ T. de Seynes, Comptes Kendus, 1S66 ; Rees, Bol. Zcitsdir. 1869 ; 

 Hansen, Carhberg Laborai . 18S3. 



