60 THIRD EEPORT — 1833. 



ration of the phenomena which it associates. This enumera- 

 tion will comprehend a greater or a smaller number of particu- 

 lars, according to the station in the scale of living beings which 

 is occupied by the object of survey. In its simplest manifesta- 

 tion, the principle of life may be resolved into the functions of 

 nutrition, secretion and absorption. It consists, according to 

 Cuvier, of the faculty possessed by certain combinations of 

 matter, of existing for a certain time and under a determinate 

 form, by attracting unceasingly into their composition a part of 

 surrounding substances, and by restoring portions of their own 

 substance to the elements. This definition comprehends all 

 the essential phenomena of vegetable life. Nutritive matter is 

 drawn from the soil by the spreading fibres of the root, through 

 the instrumentality of spongioles or minute turgid bodies at 

 their extremities, which act, according to Dutrochet, by a power 

 which he has called ' endosmosis.* The same agency raises the 

 nutrient fluid through the lymphatic tubes to the leaves, where 

 it seems to undergo a kind of respiratory process, and becomes 

 fit for assimilation. These changes, and the subsequent pro- 

 pulsion of the sap to the different parts and textures, plainly 

 indicate independent fibrillary movements, which are repre- 

 sented in animal life by what Bichat has termed * the pheno- 

 mena of organic contractility'. The power residing in each 

 part of detecting in the circulating fluid, and of appropriating, 

 matters fitted to renovate its specific structure, is designated in 

 the same system by the term * organic sensibility'. 



Ascending from the vegetable to the animal kingdom, the 

 term ' life' advances greatly in comprehensiveness. The exist- 

 ence of a plant is limited to that portion of space in which acci- 

 dent or design has inserted its germ; while animals are for 

 the most part gifted with the faculties of changing their place, 

 and of receiving from the external world various impressions. 

 Along with the general nutritive functions, the higher attri- 

 butes of locomotion and sensation are therefore comprised in 

 the extended compass of meaning which the term ' life' acquires 

 with the prefix ' animal'. The nutritive functions, too, emerging 

 from their original simplicity, are accomplished by a more com- 

 plex mechanism, and by agencies further removed from those 

 which govern the inanimate world. 



Locomotion is efi^ected either by means of a contractile tissue, 

 or of distinct muscular fibres. These fibres have been said to 

 consist of globules resembling, and equal in magnitude to, those 

 of the blood, disposed in lines, in the elementary cellulosity, which 

 by an extension of the analogy is compared to serum. But the 

 latest microscopical observations of Dr. Hodgkin are opposed 



