OF VITAL ACTIONS IN GENEKAL. 33 



alcohol and carbonic acid. If the decomposition of the membrane have 

 proceeded further, a different product will result ; for instead of alcohol, 

 lactic acid will be generated. And in a further stage of decomposition, 

 the ferment is the means of producing butyric acid (the fatty acid of 

 butter). There appears no improbability, then, in the idea, that the 

 influence exerted by the germinal molecule is of an analogous nature ; 

 and that it operates upon the elements of the surrounding water arid 

 carbonic acid, according to purely chemical laws, uniting the carbon 

 with the elements of water, and setting free the oxygen. This result of 

 the nutritive operations of the simply cellular plants may be easily veri- 

 fied experimentally, by exposing the green scum, which floats upon 

 ponds, ditches, &c., and which consists of the cells of a minute Crypto- 

 gamic Plant, to the influence of light and warmth beneath a receiver ; 

 it is found that oxygen is then liberated, by the decomposition of the 

 carbonic acid contained in the water. We shall presently have to return 

 to the consideration of the Chemical phenomena of living beings ; and 

 shall pass on, therefore, to consider those to which no such explanation 

 applies. 



30. The second stage in the nutritive process consists in the appro- 

 priation of the new products thus generated to the enlargement of the 

 living cell-structure ; a phenomenon obviously distinct from the pre- 

 ceding. It is well to observe, that this process, which constitutes the 

 act of Organization, may be clearly distinguished in the higher Plants 

 and Animals, as consisting of two stages ; the first of these being that 

 of assimilation, which consists in the further preparation or elaboration 

 of the fluid matter, by certain alterations whose nature is not yet clear, 

 so as to render it plastic or organizable ; the second being the act of 

 formation, or the conversion of the organizable matter into the solid 

 texture, in which process the properties that distinguish that texture 

 come to manifest themselves. Thus, for example, we do not find that 

 a solution of dextrin (or starch-gum) is capable of being at once applied 

 to the development of Vegetable tissue, although it is identical in com- 

 position with cellulose ; for it must first pass through a stage, in which 

 it possesses a peculiar glutinous character, and exhibits a tendency to 

 spontaneous coagulation, that seems like an attempt at the production 

 of organic forms. And in like manner, the albumen of Animals is evi- 

 dently not capable of being applied to the nutrition of the fabric, until 

 it has been first converted into fibrin ; which also is distinguished by its 

 tenacious character, by its spontaneous coagulability, and by the fibrous 

 structure of its clot. Now, in both these cases, there is probably some 

 slight modification in chemical composition, that is, in the proportions 

 of the ultimate elements ; but the principal alteration is evidently that 

 which is effected by the rearrangement of the constituent particles ; so 

 that, without any considerable change in their proportions, a compound 

 of a very different nature in generated. Of the possibility of such 

 changes we have abundant illustrations in ordinary Chemical pheno- 

 mena ; for there is a large class of substances, termed isomeric, which, 

 with an identical composition, possess chemical and physical properties 

 of a most diverse character. 



31. But we cannot attribute the production of Fibrin from Albumen, 



3 



