CELL-LIFE. 553 



recombination in the plants in the single cell, is a " vital " property, one 

 not possessed "by dead matter. 



Fermentation. The succession of phenomena exhibited is connected 

 with a series of chemical changes which are probably somewhat as 

 follows. The whole of the processes are accompanied by evolution of 

 carbonic dioxide. The earlier growth can go on without access of 

 oxygen, as is evident from the fermentation proceeding in large vats 

 with a stratum of carbonic acid several feet thick over the surface of 

 the liquid; the growth in the latter stages takes place most freely 

 with access of air. The original liquid contains grape-sugar (glu- 

 cose), or dextrine, and nitrogenous matters. If the yeast-cells be kept 

 out from this fluid no fermentation occurs ; but if yeast be added the 

 protoplasmic matter of the yeast decomposes a portion of the fluid, 

 forming cell-membranes. The chemical action set up disturbs the com- 

 bination in the rest of the sugar, which loses carbonic dioxide and 

 becomes alcohol. If the growth of the Fungus continues, the alcohol 

 becomes decomposed (seemingly by contact-action again), absorbs oxygen 

 from the atmosphere, and becomes acetic acid. 



It is not clear in most cases to what extent the Fungus is nourished 

 on the alcohol, or on the saccharine or dextrinous matters mixed with 

 the alcohol. To form cell-membrane from alcohol would require the 

 absorption of a large quantity of oxygen, and the formation of much 

 acetic acid and water. The growth of the Vinegar-plant in solution of 

 sugar, then, would appear to cause simple liberation of water, while the 

 contact-action in like manner decomposes the sugar into acetic acid. The 

 ''mother of vinegar" finally is developed at the expense of acetic acid, 

 with separation of water. 



The processes here briefly described cannot be disregarded when we 

 inquire into the mode in which plants generally take up their food. 

 Not only do the Fungi all feed in this way as, for instance, the 

 Dry-rot (Memliu9\ which lives on the dead substance of timber, or the 

 parasites like Pttccm*<8. the Potato-fungus, c., which send their myce- 

 lium into the tissues of living plants to feed upon their juices but the 

 same laws evidently regulate the nutrition of the colourless parasites, 

 such as Orobanchacese (p. 325), and the Balanophorads and allied plants 

 (p. 354). 



Following out this train of reasoning, we are irresistibly led to 

 the conclusion that the same processes may occur in all plants 

 under particular circumstances, although not absolutely necessary 

 except at certain stages of growth. 



Germination. In germination, doubtless the decomposition of 

 the store of starch &c., with evolution of carbonic dioxide, during 

 the recommencement of cell-development, is a phenomenon essen- 

 tially similar to the development of the Yeast-plant. And we 

 cannot find any reason to suppose that the roots of plants can 

 refuse to take up organic matters existing in a state of solution in 

 the soil. The extent to which growth may be stimulated, without 

 access of light, by profuse supplies of organic food, is strikingly 

 illustrated by the many succulent vegetables cultivated for the table, 



