ECONOMIC MYCOLOGY. 241 



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 microscope. 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 degi-ees, for at that 

 temperatui'e 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 alcohol are substituted for sugar is still a mystery, 

 and, like other mysteries connected with vitahty, 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 disappeared. The 

 slight difference is caused by the formation of other comj)ounds 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 growing 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 intra-cellular theory. Pasteur is of opinion that 

 the vital action of the cell 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 outside free to arrange themselves into carbonic acid and alcohol. 

 This is the extra-cellular 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 will forthwith 

 set up their microscopes and become students themselves. The facts 

 observed at the time may often appear isolated and of httle consequence, 

 but subsequently by combination and further discovery they may become 

 of the greatest value. Minute scientific research always precedes the 

 application 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 gi-eat and unexpected 

 changes. 



The British Association. — The highly successful Dublin Meeting was 

 brought to a close on August 21st, under the presidency of Mr. William 

 Spottiswoode, M.A., F.R.S., LL.D., D.C.L., &c. The total sale of tickets 

 was 2,578. Next year's meeting will be held at Sheffield, commencing 

 August 6th. 



