62 THE CELL DOCTRINE. 



But not only is the relation of these cells to each 

 other and to the central cell whence they took their 

 origin mutually dependent, but in many animal tis- 

 sues, at least, we have the so-called intercellular sub- 

 stance in a certain definite manner dependent upon 

 the cell or cells which it surrounds, "so that certain 

 districts belong to one cell and certain others to 

 another." Especially is this the case in pathological 

 processes, where sharp boundaries may often be drawn 

 between cell territories. Herein have we the second 

 distinguishing character of Virchow's theory. 



There are also a third and fourth distinctive fea- 

 tures. It has already been explained that the prin- 

 ciple of the theory of Schleiden and Schwann lay in 

 this, that every tissue, healthy or morbid, results 

 from the apposition of cells, and that this principle 

 is still observed as correct, the mode of origin of the 

 primary cell being alone the object of dispute. Ac- 

 cording to Yirchow, however, it is a special cell 

 which becomes the starting-point of physiological 

 and pathological processes, and by its various meta- 

 morphoses constitutes the healthy or morbid tissue, 

 excepting epithelial formations. This cell is the 

 so-called connective tissue corpuscle, or cell of the con- 

 nective tissue, which, according to Virchow, is a cell 

 with all its essential constituents (cell wall, cell con- 

 tents, and nucleus), and not a nucleus alone, as orig- 

 inally described by Schwann, and later by Ilenle* 

 and Landois.f From the well-known universal 



* Henle, Bericht iiber die Fortschritte d. Physiol., 1859; 1866, 

 p. 41. 

 f Landois, Zeits. f. wiss. Zool., Bd. xvi, p. 1. 



