GROWTH OF FUNGI AND OF INFUSORIA. 329 



at appreciable distances. In this respect, therefore, the two 

 theories are not opposed to each other. They deviate, however, 

 in this, that the one theory considers yeast as a body, the smallest 

 particles of which are in a state of motion and transposition, and 

 that, by virtue of this state, the particles of sugar in contact with 

 it are thrown into the same state of change, while the other 

 theory asserts, that the particles of yeast are little fungi, which 

 are developed from germs or seeds falling into the fermenting 

 liquid from the air; and that in this they grow at the expense of 

 the substances containing nitrogen, which are thus converted into, 

 and separated as, fungi. The particles of sugar in contact with 

 the fungi are supposed to be converted into carbonic acid and 

 alcohol, which, in other words, signifies, that the act of vegetation 

 effects a disturbance in the chemical attractions of the elements 

 of the sugar, in consequence of which they arrange themselves 

 into new compounds. 



Gay-Lussac showed by experiments that the juice of grapes 

 expressed apart from air, under a bell-jar full of mercury, did 

 not er.ter into putrefaction, although it did so in the course of a 

 few hours when air was admitted. The same chemist also showed, 

 that fermentation immediately commences on the introduction of 

 oxygen gas, of which a quantity is absorbed equal only to the 

 T^T tn P art °f tne volume of carbonic acid evolved during the 

 fermentation. It scarcely can be supposed, that the germs of 

 fungi exist in chlorate of potash or black oxide of manganese, out 

 of which the oxygen was obtained ; and hence it is difficult 

 to ascribe to a growing vegetation the causes of the decom- 

 position. 



Gay-Lussac further showed, that the juice entered into fer- 

 mentation on being connected with the wires of a galvanic battery, 

 under circumstances, therefore, which quite excluded the intro- 

 duction of every foreign body. Hence the view, that the fer- 

 mentation of sugar is effected by contact with growing plants, 

 must presuppose that living beings, plants for example, may be 

 formed and developed without germs or seeds- — a circumstance 

 in direct contradiction to all observation regarding the growth 

 of plants. 



It is certain that sponges and fungi, growing in places from 



