FERMENTATION. 97 



bodies which come into contact with them." Thi: 

 was nothing more than an extension of Willis' and Stahl'i 

 view of fermentation ; they held that a ferment is a bodj 

 which has a peculiar internal motion which is capable o: 

 being transmitted from the ferment to a fermentable matter 

 So fascinating and plausible a theory, of course, received wid( 

 recognition, and until Pasteur's admirable demonstrations o 

 his theory of fermentation were made, had received ver3 

 general acceptance, especially amongst German chemisti 

 and biologists. The mechanical theory and the theory o 

 catalytic forces as used in the old sense have now beer 

 laid aside, and the vitalist theory — expressed in the following 

 words by Turpin : " Fermentation as effect, and vegetatior 

 as cause, are two things inseparable in an act of decom 

 position of sugar " — has taken the field against all opponents 

 This theory is that living organisms build up structure; 

 and develop energy from the materials in which the] 

 live, and break up by their vital activity, either directly 

 or through a soluble ferment, the sugar in which the] 

 grow. In this theory albuminoid material is considerec 

 to be necessary for the process of fermentation or decom 

 position only in so far as it is required for the nutritioi 

 of the micro-organism, it being denied that nitrogeneou 

 elements play any such part, as that ascribed to them bi 

 Liebig, of producing the molecular motion, which bring 

 about the splitting up of the sugar, by undergoing a spon 

 taneous decomposition. Albuminoid material, in fact, i 

 merely an accompaniment of the process of fermentation— 

 a necessary one, no doubt, but one not in any way playinj 

 the part of causal factor. 



What takes place in brewing, a process which, though unti 

 recently incompletely understood, has long been carried oi 

 on an enormous scale in most northern countries ? Malt i 

 barley in which a certain proportion of the starch of th^ 

 grain has been converted into sugar by the process knowi 

 as "malting." This consists essentially in moistening th' 

 grain several times, keeping it at a temperature high enougl 

 to promote its sprouting, during which a substance callei 

 diastase is developed as the result of the vital activity c 

 the cells in the germinating grain which acting on the stard 

 converts it into sugar. As soon as this takes place th 

 sprouting is stopped by raising the temperature and then b; 



