THE GENESIS OF LIVING ORGANISMS 191 



however exact the historian of art may be, the science of 

 style can never attain to the exactness of morphology ; for 

 the arbitrariness of the human architect has to be taken into 

 account, whereas morphology finds its support in the laws of 

 Nature herself. 



THE MOSAIC THEORY 



Undoubtedly we are entitled to regard each organism as 

 a cell-mosaic ; in so doing, we refer to the cell as the smallest 

 stone in the mosaic, and from this all the genetic building- 

 stones are composed. Now, if this body-mosaic arises from 

 a germ-cell, we may ask, " In what form are its rudiments laid 

 down in the germ ? " 



If to help us in answering this question we select for 

 comparison the genesis of a mass of crystals from the mother- 

 liquor, we see that formation of these, beginning at separate 

 points, gradually spreads through the whole. The sequence 

 and arrangement in which this proceeds depends on the con- 

 dition of the mother-liquor at the time, and. mainly on the 

 position of minute foreign bodies suspended in it, which serve 

 as points of deposition of the crystallisation. 



If we imagine the position of these freely movable points 

 to be determined by a hidden structure, then from a chemically 

 homogeneous liquid the same crystalline structure will always 

 emerge, whenever the liquid contains within it the same 

 system of points of crystallisation. . The presence of a hidden 

 framework of this kind would be necessary, if the crystalline 

 structure were to serve a definite mechanical use. And so 

 we put a hidden framework even into the germ of the organism, 

 because the germ always allows a mechanism to proceed 

 from it. 



The simplest way we can imagine this framework is to 

 assume a micro-mosaic in the germ-cell itself, simpler perhaps 

 than the macro-mosaic, but of necessity already containing 



