214 THEORY OF THE CELLS. 



metabolic phenomena resides in that definite mode of arrange- 

 ment of the molecules which occnrs in crystals, combined with 

 the capacity which the solution has to penetrate between these 

 regularly deposited molecules (by means of which, presuming 

 the molecules to possess polarity, a sort of galvanic pile will 

 be formed), and that the same phenomena would be observed 

 in an ordinary crystal, if it could be rendered capable of imbi- 

 bition. And then perhaps the differences of quality in the 

 metabolic phenomena depend upon their chemical composition. 

 In order to render tenable the hypothesis contained in the 

 second point, it is merely necessary to show that crystals capable 

 of imbibition can unite with one another according to certain 

 laws. If at their first formation all crystals were isolated, if 

 they held no relation whatever to each other, the view would 

 leave entirely unexplained how the elementary parts of or- 

 ganisms, that is, the crystals in question, become united to 

 form a whole. It is therefore necessary to show that crystals 

 do unite with each other according to certain laws, in order to 

 perceive, at least, the possibility of their uniting also to form 

 an organism, without the need of any further combining 

 power. But there are many crystals in which a union of this 

 kind, according to certain laws, is indisputable ; indeed they 

 often form a whole, so like an organism in its entire form, 

 that groups of crystals are known in common life by the names 

 of flowers, trees, &c. I need only refer to the ice-flowers on the 

 windows, or to the lead- tree, &c. In such instances a number 

 of crystals arrange themselves in groups around others, which 

 form an axis. If we consider the contact of each crystal with 

 the surrounding fluid to be an indispensable condition to the 

 growth of crystals which are not capable of imbibition, but that 

 those which are capable of imbibition, in which the solution can 

 penetrate whole layers of crystals, do not require this condition, 

 we perceive that the similarity between organisms and these 

 aggregations of crystals is as great as could be expected with 

 such difference of substance. As most cells require for the 

 production of their metabolic phenomena, not only their pe- 

 culiar nutrient fluid, but also the access of oxygen and the 

 power of exhaling carbonic acid, or vice versa ; so, on the other 

 hand, organisms in which there is no circulation of respiratory 

 fluid, or in which at least it is not sufficient, must be developed 



