LECT. I. ORGANIZATION. 23 



difference which exists between the effects of the great 

 forces of nature, according as the body in which they oc- 

 cur is living and organized, or inorganic and dead. 



What, then, is the cause of these extraordinary differ- 

 ences in the modes of action of physical agents on living 

 beings and on other bodies of nature ? Here is a primary 

 question of the highest importance, and one to which the 

 existing state of our knowledge furnishes no satisfactory re- 

 ply. But let us not, on that account, abandon the analogies 

 which the physical sciences offer us ; a ray of light which 

 penetrates a piece of glass or a body of water, in an oblique, 

 direction, deviates from the straight line, whilst, on the con- 

 trary, if it fall on a crystal of carbonate of lime (calcareous 

 spar) it is split into two other rays, each of which deviates 

 from the direction of the primitive ray, but in unequal de- 

 grees. The cause of the difference of these phenomena 

 resides in the difference of physical structure existing be- 

 tween glass and crystallized calcareous carbonate, and per- 

 haps also in the different chemical nature of their molecules. 

 These modifications of the luminous ray, however, arise 

 more from diversity of structure, or the peculiar arrange- 

 ment of the molecules, than from differences of chemical 

 composition. Indeed, we know that glass acts differently 

 upon rays of light, according as it is more or less com- 

 pressed in different directions, without its chemical compo- 

 sition undergoing any change. 



Who could confound an organized being with an inor- 

 ganic body ? In these groups of closed vesicles, of diffe- 

 rent dimensions, united and disposed in anirregular manner, 

 there is assuredly something essentially different from a mass 

 of polyhedral particles, composing a crystal. To say, with 

 some micrographers, that organization is crystallization ef- 

 fected in a liquid which the first formed crystals imbibe, is 

 equivalent to admitting that the structure of a stalactite is 



