I 



74 KUTRITIOX OF AN ELEMENTARY PART. 



one who really studies tlie elementary parts of tissues 

 and investigates the changes which occur as the bio- 

 plasm passes through various stages of change until 

 the fully developed structure results, will be careful 

 not to accept T\4thout due consideration the vague 

 generalisations of those w"ho persist in authoritatively 

 declaring the dogma that the changes occuring in 

 cell growth are merely mechanical and chemical, 

 although they are unable to produce by any means at 

 their disposal a particle of fibrine, a piece of cartilage; 

 or even a fragment of coral. They avoid the diffi- 

 culty as regards the bioplasm by ignoring its exist- 

 ence, and attribute to a "molecular machinery" 

 which the mind cannot conceive, and which cannot 

 be rendered evident to the senses, all those wonderful 

 phenomena which are really due to vital power. 



113. Nutrition of an elementary part. — We may 

 now discuss what goes on during the nutrition of a 

 " cell" when it is in a living state. I need not repeat 

 that the active changes are exclusively confined to the 

 bioplasm, and that the formed material is passive, 

 though it may act like a filter, permitting some things 

 to pass and interfering with the passage of others. 

 Well, then, in nutrition, pabulura becomes bioplasm 

 to compensate for the bioplasm which has been con- 

 verted into formed material. Now, let us consider 

 the order of these changes, and endeavour to express 

 them in the simplest possible manner. Let the bio- 

 plasm which came from pre-existing bioplasm be called 

 a ; the non-living pabulum, some of the elements of 

 which are about to be converted into bioplasm shall 

 be 6 ; and the non-living formed material resulting 

 from changes in the bioplasm, c. It is to be remarked 

 that h does not contain c in solution, neither can c be 

 made out of h, unless & first passes thi'ough the con- 

 dition a, and a cannot be formed artificially, but 

 must come from pre-existing a. In all cases h is 

 transformed by a into a, and a undergoes conversion 



