390 ANATOMICAL AND PATHOLOGICAL OBSERVATIONS. 



is formed at first, not by simultaneous formation of its parts, 

 but by the successive development 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 inde- 

 pendent vitality, but that there is, in addition, a division of 

 the whole into departments, each containing a certain number 

 of simple or developed cells, all of which hold certain rela- 

 tions 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 develop- 

 ment, 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 

 pecidiar to the textures, and those which belong to the 

 organs. The nutritive centres of the textures are in general 

 permanent. Those of the organs are in most instances pecu- 

 liar 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 succes- 

 sive broods of young ceils, which from time to tune fill the 

 cavity of their parent, and carrying with them the ceU-wall 

 of the parent, pass off in certain directions, and under various 

 forms, according to the texture or organ of wliich their parent 

 forms a part.* 



For the first consistent account of the development of cells from a parent 



