22 BIOPLASM MUST BE NOURISHED. 



growth, one within the other. The inmost of all is 

 the last produced, and this is often found to be 

 endowed with powers or properties different from 

 those manifestefi by the bioplasm which preceded it, 

 in which it was developed, which it is to replace, and 

 which perhaps is to be entirely destroyed in order 

 that the last, the newly developed bioplasm, may 

 flourish for a time, and then give place to new centres 

 which in their turn will appear within it. These 

 little spots are known as "nuclei." The spot within 

 the nucleus is the " nucleolus." (See § 85.) 



31. Bioplasm must be nourished.— Every kind of 

 living matter when it increases is said to be nourished. 

 In order that the act of nutrition may occur it is 

 necessary that the material constituting the fcibulum 

 or nutrient matter should be brought very close to the 

 living matter. A part of the latter then moves 

 towards the non-living pabulum. Bioplasm through- 

 out its life tends to move away from its centre. Its 

 particles seem to be impelled centrifugally towards 

 any nutrient matter that may be near to it. Whether 

 or not the non-living pabulum is taken up and con- 

 verted into the living depends upon a number of 

 circumstances which the living is utterly powerless 

 to occasion, influence, control, or modify. But these 

 external conditions being favourable and the pabulum 

 being very near to the living matter, some of the 

 latter is taken up by the living bioplasm, which com- 

 municates to certain of the non-living constituents its 

 own particular properties or powers. Such essentially 

 is the phenomenon of nutrition, which is universal in 

 the living world, and which in fact consists of the 

 taking up of the non-living matter by living matter 

 and its incorporation with it. Tlie non-living is made 

 to live by the agency of that which is already living. 

 The process of nutrition of an elementary part is 

 more particularly described in Lecture V. 



38. How pabulum may be brought near to the bio- 



