352 



SIMPLEST FORMS OF FUNGI 



-YEAST-PLANT. 



always a multiple of two), which are projected from the apothecia 

 with some force, the emission being kept up continuously for 

 some time : this discharge seems to be due to the different effect 

 of moisture upon the different layers of the apothecium. "When 

 and how the act of Fecundation is accomplished, is a matter still 

 hidden in obscurity ; and the problem is one which will only 

 be resolved by a combination of sagacity, manipulative skill, and 

 perseverance, on the part of Microscopic observers who may 

 devote themselves to the study.* 



263. In the simplest forms of Fungi we again return to the 

 lowest type of Vegetable existence, namely, the single cell ; and 

 such, if perfect Plants, would properly take rank among the lowest 

 Protophytes. But there is good reason for regarding many — 

 perhaps all — of those which seem most simple, as the imperfectly 

 developed states of other Plants, which, if they attained their full 

 evolution, would present a much more complex structure. This 

 is the case, for example, with the Torula cerevisice or 'yeast- 

 plant,' which so abounds in Yeast that this substance may be said 

 to be almost entirely made up of it. When a small quantity of 

 Yeast is placed under the Microscope, and is magnified 300 or 400 

 diameters, it is found to be full of globules, which are clearly Cells ; 

 and these cells vegetate, when placed in a fermentible fluid con- 

 taining some form of Albuminous matter in addition to Sugar, in 

 the matter represented in Fig. 165. Each Cell puts forth one or 

 two projections, which seem to be young cells developed as buds 

 or offsets from their predecessors ; these, in the course of a short 

 time, become complete cells, and again perform the same process ; 

 and in this manner the single cells of yeast develope themselves, 

 in the course of a few hours, into rows of four, five, or six, which 

 remain in continuity with each other whilst the plant is still 

 growing, but which separate if the fermenting process be checked, 



Torula cerevisice, or Yeast-Plant, as developed during the pro- 

 cess of fermentation : — a, b, c, d, successive stages of Cell-multi- 

 plication. 



* For the latest information on this subject, see Dr. Lauder Lindsay's 

 Memoir on Polymorphisne in the Fructification of Lichens ("Quart. 

 Journ. of Microsc. Science," Vol. viii., N.S., 1868, p. 1), and the authors 

 therein referred to. 



