THE MICROSCOPE. 87 
Bruyne records (Bulletin Roy. Acad. Sci. Belg., LVI, 1888) his 
belief that it does not communicate with the exterior, and that it is 
not possessed of excretory functions. Prolonged study tends to show 
that the contained fluid is not expelled from the protozoan, but that 
it is forced to other parts, to again return to form the vacuole. 
He would rather regard it as of respiratory and circulatory functions, 
and thinks that the contained fluid may possibly have nutrient 
qualities. 
BOTANY 
Tue Nutritive Processes in Saccuaromyces.t The study of the 
nutritive processes of these fungi has been undertaken by Vine, who 
describes, 1, the nature and condition of the nutrient material, and, 
2, the manner in which such nutriment finds its way within the organ- 
ism. The fact that various species of Saccharomycetes will thrive in 
other than saccharine fluids,—one containing mineral salts only, for 
example,—leads to the conclusion that whatever other materials may 
be absorbed, the cell wall must necessarily be pervious to certain 
inorganic salts. The cultivation of S. cerevisic in infusions of malt 
containing various amounts of ammonia or nitrogen salts, shows that 
the vigor of the cell and the process of multiplication is visibly 
increased by the mineral additions, though not always with regular- 
ity. On the other hand, in cultures in solutions of cane sugar, with 
or without the addition of nitrogen, and ammonia salts and alkaline 
phosphates, the vitality of the cells is maintained, but the increase 
of cells is limited and their vigor visibly declines. If these cells 
are now placed in a fresh sugar solution, they will exert but little 
decomposing action, and their vitality will come to a standstill. If 
they are now removed to a weak malt infusion, or a solution of sugar, 
either containing besides the saccharine matter, nitrogen and mineral 
salts, the cell-contents will again fill up the cells, and the process 
of multiplication will begin and continue as long as the cultivating 
medium remains suitable. Malt infusion deprived of its crystalliza- 
ble nitrogen by dialysis, has about the same effect on the growth of 
the cells as the sugar solution. The author is of the opinion that 
compounds of an amide character play an important part, and that 
the suitability of a liquid as a nutrient medium for the growth of 
saccharomyces depends much on the amount of resolution in this 
*Under this heading will be included all Abstracts relating to the various 
departments of Botany. 
+ Journal of Microscopy, Jan’y, 1889, p. 9. 
