2C8 Dynamic Theory. 



cells of the fruit itself after air had been denied to them. When, 

 moreover, the cells were destroyed by bruising, no fermentation en- 

 sued. The fermentation was the correlative of a vital act and it ceased 

 when life was extinguished. Ludersdorf was the first to show by this 

 method that the yeast had acted not as Liebig had assumed in virtue of 

 its organic, but in virtue of its organized character. He destroyed the 

 cells of yeast by rubbing them on a ground glass plate, and found that 

 with the destruction of the organism, though its chemical constituents 

 remained, the power to act as a ferment totally disappeared. " 



We thus perceive that the cells of fruit are alive in the same sense that 

 the cells of yeast are, at least to the extent of breathing, and like yeast 

 and certain other parasitic cells, can take the oxygen required for their 

 respiration from a carbon compound when they cannot get it free. 

 These cells are probably reproductive by fission or germination so long as 

 nourishment is supplied to them, that is during the growth of the fruit. 

 This is practically the principal mode of growth by both Torula and 

 Saccharomyces, although this mode is supplemented in the latter by the 

 power to form spores also, under proper conditions. If the cells of 

 fruit or yeast be broken up by mechanical means, or by too much heat, 

 they are killed and cease to breath or to grow and bud. 



We are indebted to Prof. Tyndall's book for the description of the 

 mode of making ' ' That fiery and intoxicating spirit known in commerce 

 as Kirsch or Kirschwasser. " 



A cask with a very large bung-hole is nearly filled with cherries. The 

 bung-hole is closed tightly and the cherries left for fourteen days. At 

 the end of this time the bung being removed, the air in the space above 

 the cherries is found to be converted into carbonic acid gas. The con- 

 tents of the cask are emptied into a copper still and evaporated by heat; 

 the vapor passing through a cooled pipe and being condensed into the 

 alcoholic liquor " Kirsch. " No ferment is put into these cherries but 

 they are expected to furnish their own ferment, and they always do. 



The fermentation of wine is also automatic. The wine maker depends 

 on the grape juice to furnish its own ferment, and has done so for 3,000 

 years without disappointment. In the fermentation of wine ( and I sup- 

 pose of the "Kirsch" too, though it is not definitely so stated) the 

 Torula (or rather Saccharomyces) is invariably the active agent. In 

 answering the question, where does it come from, Tyndall states on the 

 authority of Pasteur, that " at the time of the vintage microscopic par- 

 ticles are observed adherent both to the outer surface of the grape and 

 to the twigs which support the grape. " Some of these seen through a 

 microscope look like "organized cells." If they are brushed off and 

 put into the pure inert juice of the grape they will produce fermentation 

 in forty-eight hours, and < ' our familiar Torula is observed budding and 



