BY K. GREIG SMITH. 669 



The nodule yeasts have always a tendency to form a more or 

 less gelatinous capsule. In peptone-glucose fluid this is very thin, 

 while in solid media it is more or less bulky. Under some con- 

 ditions, and notably in sucrose fluids, the cells are collected in 

 zoogloea films, tufts and filaments. They are very prone to collect 

 round foreign solid particles, such as fragments of cotton wool, 

 and when this occurs there is presented the appearance of a 

 microscopically wide tube containing the organisms. The capsule, 

 when swollen and muciltiginous, gathers more or less towards the 

 middle of the simple cell, or of the elongated or branching com- 

 pound cells, and by staining equally with the cell produces many 

 odd forms. Among the.se odd forms there is a lenticular shape, 

 and a sphere with two or three projecting points : the two pro- 

 jecting points cause the organism to appear like the planet 

 Saturn. The other varieties of form may be called hat-shapes. 

 These irregular appearances are only observed when stains are 

 used that colour the capsule as deeply as the cell. The relation 

 between the capsule and the organism may be demonstrated by 

 staining with carbol-fuchsin, and washing most of the stain out 

 of the capsule with dilute alcohol. The cell then appears of a 

 deep red colour, and the capsule pink. 



In my endeavour to obtain a preparation showing the flagellum 

 by means of which the cell presumably is enabled to move about, 

 many cultures of the organism were tried in various ways. As 

 a result of these trials it became evident that the suspension of 

 an agar culture in water or normal saline was not suitable. 

 Ultimately peptone-glucose fluid cultures were used in the 

 undiluted condition, spread on clean cover-glasses, air-dried 

 and fixed in 5-10 per cent, formalin solution. The formalin 

 solution, while fixing the organisms, probably also extracts 

 some of the soluble constituents of the film which might take 

 up the mordant and become stained. The formalin was washed 

 oft' with distilled water, and the cover-glass immersed in 

 Coerner-Fischer mordant that had been warmed and filtered. 

 The watch-glass containing film and mordant was kept warm by 

 placing it over the very small flame of a microchemical burner. 



