YEAST PLANT. 



299 



it smaller filaments with small bead-like bodies upon the 

 apex, piled one upon the other, or, more properly speak- 

 ing, strung together ; these, again, are surmounted by- 

 larger spores of a discoid shape filled with granular 

 matter, and others which are quite empty. Those of the 

 aspergillus are apparently without granular matter or 

 nuclei, and are more highly refractive. The puccinia are 

 club-shaped, the very rapid growth of the spores arid 

 spawn of which appears to exert a specific and peculiarly 

 exhaustive action over the tissues of the plant on which it 

 feeds. Plate I. No. 12, represents a portion of the mould 

 taken from a saccharine solution. 



The yeast plant, in its most perfect condition, is chiefly 

 made up of globular vesicles, measuring, when fully 

 grown, about the 2"sWth of an inch in diameter. The 

 older cells are filled with granular or nucleated matter ; 

 the nucleus rapidly increases, and nearly fills up the parent 

 cell, which then becomes ovoid, and ultimately the young 

 cell buds out and is separated from the parent. Some- 





Fig. 159.— .i diagrammatic representation of the development of the Yeast Pla.nt. 



No. 1, Fresh Yeast: No. 2, one hour after adding it to wort; No. 3, three 

 hours ; No. 4, eight hours ; No. 5, third day, after which jointed filaments 

 are produced. 



times other and smaller ceils are formed within the young 

 one before it leaves the parent globule. This process goes 



