69 



the microscope to form an additional internal membrane, which, becoming sep- 

 tose, divides the protoplasm into three or four parts, each of these parts becomes 

 sperical, opaque, and ultimately detached as a spore. The nutrition of yeast in 

 one particular resembes that of the higher order of plants, for it is supplied with a 

 soluble nitrogenous ferment wliich enables it to alter saccharose. This nitroge- 

 nous matter may be separated by washing the cells in water. Every time they 

 are washed some of it is dissolved out. It is always acid, and if neutralised 

 becomes again acid. Directly that it comes in contact with saccharose, the latter 

 is forced to take up an additional atom of water, and thus become glucose. The 

 multiplication of the cells of yeast by budding is a process that may be easily 

 watched under the miscroscope. If the temperature is kept between 75 and 90 

 degrees, one or more cells may be seen to arise in succession, or even at the same 

 time, from a parent cell, and form themselves into short irregular chains. The 

 vitality of yeast is dormant below 50, and is destroyed, as we should expect, at 

 140 degrees, for at that temperature nitrogenous matter begins to coagulate. The 

 growth of yeast is checked if the solution of sugar is too dense, or if the quantity 

 of alcohol is too large. Attempts have frequently been made by physiologists to 

 account for these phenomena, but how and why carbonic acid and acohol are sub- 

 stituted for sugar is still a mystery, and like other mysteries connected with 

 vitality, is likely so to remain. It has been ascertained that the weight of the 

 alcohol and carbonic acid is nearly equal to the weight of the sugar which has dis- 

 appeared. The slight difference is caused by the formation of other compounds 

 that only appear in minute quantities. Some think that the glucose and other 

 materials that form the food of the yeast plant penetrate the cell by osmose, and 

 there, after undergoing transformation, are assimilated and converted into grow- 

 ing cells and tissues, while at the same time disassimilation is proceeding, the 

 worn-out tissues are changed into alcohol and carbonic acid, and are eliminated as 

 excrementitious matter. This may be called the intracellular theory. Pasteur is 

 of opinion that the vital action of the shell causes decomposition of the glucose, 

 and that a portion of its oxygen penetrates the cell membrane and takes part in 

 the process of assimilation, while the other constituents of the glucose are left out- 

 side free to arrange themselves into carbonic acid and alcohol. This is the 

 extra-ceUular theory. Which is correct? It remains for some one, perhaps a 

 Woolhopian, to determine. 



In this agricultural and woodland county there is abundant opportunity 

 for the study, not only of the parasitic funguses, but of most others, and as our 

 Field Club was constituted for the purpose of observing and recording all facts 

 connected with the natural history of the district, it is to be hoped that some of 

 our members wiU forthwith set up their microscopes and become students them- 

 selves. The facts observed at the time may often appear isolated and of little 

 consequence, but subsequently by combination and further discovery they may 

 become of the greatest value. Minute scientific research always precedes the ap- 

 plication of science to industry, and though little acknowledged, is at the present 

 day performing a very important part in intellectual and industrial advancement, 

 and wiU, ere long, effect great and unexpected changes. 



