THEORY OF THE CELLS. 203 



and crystals, arc, as we have observed, very different, even if 

 we regard merely the plastic phenomena of the cells, and Leave 

 their metabolic power (which may possibly arise from some 

 other peculiarity of organic substance) for a time entirely out 



of the question. 



Is it, however, possible that these distinct ions arc only 

 secondary, that the power of crystallization and the plastic 

 power of the cells are identical, and that an original difference 

 can be demonstrated between the substance of cells and that 

 of crystals, by which wc may perceive that the substance of 

 cells must crystallize as cells according to the lavs by which 

 crystals are formed, rather than in the shape of the ordinary 

 crystals? It may be worth while to institute such an inquiry. 



In seeking such a distinction between the substance of eel Is 

 and that of crystals, we may say at once that it cannot con- 

 sist in anything which the substance of cells lias in common 

 with those organic substances which crystallize in the ordinary 

 form. Accordingly, the more complicated arrangement of the 

 atoms of the second order in organic bodies cannot give rise to 

 this difference ; for we see in sugar, for instance, that the mode 

 of crystallization is not altered bv this chemical composition. 



Another point of difference by which inorganic bodies are 

 distinguished from at least some of the organic bodies, is 

 the faculty of imbibition. Most organic bodies are capable 

 of being infiltrated by water, and in such a manner that it 

 penetrates not so much into the interspaces between the ele- 

 mentary tissues of the body, as into the simple struct ore] 

 tissues, such as areolar tissue, &c. ; so that they form an 

 homogeneous mixture, and we can neither distinguish par- 

 ticles of organic matter, nor interspaces filled with water. T 

 water occupies the infiltrated organic substances, just as \\ 

 present in a solution, and there is as much difference between 

 the capacity for imbibition and capillary permeatioi 

 there is between a solution and the phenomena of capillary 

 permeation. When water soaks through a layer of glue, we 

 do not imagine it to pass through pores, in the common 

 of the term; and this is just the condition of all Bubstani 

 capable of imbibition. They possess, then a doul 



nature, they have a definite form like solid bodies; but 1: 

 fluids, on the other hand, they are also permeable by anythin 



i r 



