88 NUTRITION. 



stances of which white fibrous tissue, yellow elastic tissue, 

 muscle, nerve, epithelium, &c., consist, ought to be present 

 in the white and yolk of an egg before these have undergone 

 conversion into the chick ; but we know that not one of 

 these things can be detected, and, in short, that develop- 

 ment and growth are processes essentially and absolutely 

 different from the mere deposition in a solid form of par- 

 ticles previously held in solution in a fluid. In growth the 

 substances dissolved in the fluid pabulum are completely 

 altered in composition and properties. Their elements are 

 re-arranged. If the elements of the dissolved crystalline 

 matter were torn asunder and then reunited in a different 

 way, so as to produce a new substance when deposited in a 

 solid form, crystallisation would in this one particular accord 

 with growth ; but there is not even this resemblance. A 

 crystal, then, does not grow. The fungus-like (!) accumu- 

 lation of carbon that takes place on the wick of an unsnuffed 

 candle is not growth. The deposition of geological strata, 

 the genesis of celestial bodies, are not examples of growth. 

 I think that if Mr. Herbert Spencer would carefully study 

 a growing microscopic fungus, he would modify his views 

 concerning the nature of growth^ and admit that there is an 

 essential difference between this peculiar process and the 

 above physical phenomena. 



From what has been stated in many physiological works 

 the student would be led to conclude that the tissue or 

 formed matter of a living being to be nourished, selected 

 from a mixed fluid, in consequence of some sort of affinity, 

 certain constituents adapted for its nutrition, and that those 

 substances passed at once from a state of solution to the 



