-2 CENTRES OF NUTRITION. 



not by simultaneous formation of its parts, but by the successive 

 developement of these from one centre, so the various parts arise 

 each from its own centre, this being the original source of all the 

 centres with which the part is ultimately supplied. 



From this it follows, not only that the entire organism, as has 

 been stated by the authors of the cellular theory, consists of 

 simple, or developed cells, each having a peculiar independent 

 vitality, but that there is, in addition, a division of the whole into 

 departments, each containing a certain number of simple or de- 

 veloped cells, all of which hold certain relations to one central or 

 capital cell, around which they are grouped. It would appear 

 that from this central cell all the other cells of its department 

 derive their origin. It is the mother of all those within its own 

 territory. It has absorbed materials of nourishment for them 

 while in a state of developement, and has either passed them off 

 after they have been fully formed, or have arrived at a stage of 

 growth when they can be developed by their own powers. 



Centres of nutrition are of two kinds : those which are peculiar 

 to the textures, and those which belong to the organs. The nu- 

 tritive centres of the textures are in general permanent. Those 

 of the organs are in most instances peculiar to their embryonic 

 stage, and either disappear ultimately, or break up into the various 

 centres of the textures of which the organs are composed. 



A nutritive centre, anatomically considered, is merely a cell, 

 the nucleus of which is the permanent source of successive broods 

 of young cells, which from time to time fill the cavity of their 

 parent, and carrying with them the cell wall of the parent, pass 

 off in certain directions, and under various forms, according to 

 the texture or organ of which their parent forms a part.* 



There is one form in which nutritive centres are arranged, 

 both in healthy and morbid parts, which is frequently alluded to 

 in the following chapters, and which may be named a germinal 



* For the first consistent account of the developement of cells from a parent centre, and 

 more especially of the appearance of new centres within the original sphere, we are indebted 

 to the researches of Dr. Martin Barry. Whatever may be said in opposition to Dr. Barry's 

 views regarding the functions of the blood globules, and the structure of muscular fibre, ho 

 is yet entitled, above all physiologists of the present day, to the merit of having kept steadily 

 before him in his researches, the principle of the central origin of all organic form. 



