Journal 



OF THE 



NEW-YORK MICROSCOPICAL SOCIETY. 



Vol. II. MARCH, 1886. No. 3. 



THE MICROBES OF PANARY FERMENTATION.' 



The question of panification is one of such importance that 

 it might at first sight be supposed that it would have been one 

 of the first to be solved by contemporary science. Such, however, 

 has not at all been the case, for in recent years the most contra- 

 dictory opinions upon the chemistry of bread have been emitted 

 by distinguished scientists. In order to ascertain what phenom- 

 ena accompany panary fermentation, let us rapidly pass in 

 review the various categories of bread. In the first place, we 

 have unleavened bread, the use of which is pretty much re- 

 stricted to the ceremonies of various religions. At first sight, 

 it would seem that we had nothing to do here with any ferment, 

 but, as a matter of fact, there is no such thing as unleavened 

 bread, and, supposing that such a thing really existed, we should 

 here again have some very complex phenomena to submit to 

 scientific analysis. 



In bread with leaven, we see an action analogous to that of 

 brewer's yeast upon an infusion of malt — ^to that of the sub- 

 stances commonly known as " mother of wine " and " mother 

 of vinegar." What is the nature of leaven, and what does it do 

 in dough ? In order to ans^ver these questions, it will perhaps 

 be easier to reason by analogy. The ferment contained in 

 leaven is comparable to brewer's yeast, which is a microscopic 

 plant — a Saccharomyces — that possesses the remarkable prop- 

 erty of converting the sugar of must into alcohol and carbonic 

 acid. "Brewer's yeast and mother of wine, then, modify the 

 composition of saccharine must and determine its yield of alco- 

 hol. But it is not yeasts only that act upon organic liquids, for 

 in mother of vinegar we have narrow cells, of varying length, 



'Condensed from a paper by Einile Laurent, in Ihp Bi(77p//n de In Soci'te l\n;/fiJe 

 de Botnnique dc liel(jiquc. 



