regulating Vital and Physical Phenomena. 347 



that we as yet know very little of the variety of forms which the same germ 

 may assume, according to the circumstances under which it is developed; 



How far the act of organization in itself communicates to 

 the assimilated matter the properties in question, will be a sub- 

 ject for future consideration ; at present we shall consider 

 (with Tiedemann) the property of assimilating, organizing, and 

 communicating vital properties to nutritious matter, as that 

 which most prominently characterizes living tissues. And we 

 may go farther and say, that vital properties may exist in fluids 

 also ; for the blood must be regarded as something very dif- 

 ferent from a mechanical admixture of albumen, fibrin, saline 

 matter, water, &c., since it manifests properties which can 

 scarcely be considered otherwise than vital, and presents a 

 structure which must be regarded as approaching that of orga- 

 nized matter. The same may be said of the descending or 

 elaborated sap of vegetables from which the cambium is formed; 

 since, according to the observation of Amici,* the glutinous 

 sap of the vine, when removed from the stem, assumes, during 

 the species of coagulation which it undergoes, regular forms 

 closely analogous on the one hand to those of the lower con- 

 fervas, and on the other to the elementary tissues of which the 

 fluid is the pabulum. Hence we may fully unite in the view 

 expressed by Tiedemann, " that as the solid parts obtain from 

 the general nutritive fluid matters which they receive into their 

 composition and organic structure, and to which they commu- 

 nicate their vital properties, so also do the organs which pre- 

 pare the assimilative liquids from the general nutritive fluid, 

 appear to communicate to them, by the same act, qualities that 

 give them the faculty of acting on the aliment so as to effect 

 their assimilation." 



Every tissue possesses vital properties peculiarly its own, 

 besides that which we have spoken of as common to all. Thus 

 muscular fibre is essentially characterized by its contractility, 

 nervous matter by its capability of conveying impressions, &c. 

 These vital properties all require the application of certain 

 stimuli, in order that they may be excited to activity ; and each 

 property of each organ has stimuli appropriate to itself. It is 



* Annales des Sciences Nat. t. xxi. 



