2 Prof. H. Karsten on some Phenomena of 



The primary object at present is to determine the physical 

 and chemical changes of the histological elements of cells during 

 their development and multiplication, and, by the elucidation of 

 these processes, to establish the laws which govern the origin 

 and growth of an organ or of an organism, and which collec- 

 tively make up the phenomena of life. 



The most recent treatise on human histology, that by Kolliker 

 (1862), refers to the purpose of the diflferent histological elements 

 of the cell, in respect both to its existence and its functions, 

 thus : — 1 . The external wall of the cell serves only as a defence 

 to its fluid contents (p. 39), except so far as it takes part in those 

 intrinsic vital processes which are shown to occur by changes in 

 its chemical constitution (p. 36) ; 2. the fluid cytoblastema pre- 

 eminently constitutes the living portion of the cell (p. 39) ; and, 

 3. the cell-nucleus plays the most important part in cell-formation 

 (p. 26). 



This last proposition is advanced on the understanding that 

 " the doctrine of free-cell formation in a cytoblastema has been 

 set aside'' (p. 28) — that cell-construction always coincides with 

 cell-multiplication, being a result of the fission of a parent 

 cell by means of the formation of folds in and the constriction 

 or segmentation of its internal lamina (the primordial layer), 

 although Kolliker fails not to remark that this process has, it 

 is true, not yet been satisfactorily made out. 



These fundamental doctrines of the histology of the animal 

 body, which harmonize with the prevailing, but groundless, 

 opinions upon the formation and function of the vegetable cell, 

 have, however, not been confirmed in the vegetable organism 

 with the clearness necessary for conviction. The history of 

 development has rather proved that, in those cases (Karsten, 

 op. cit. and Histologische Untersuchungen *, 1862) which have 

 been cited as furnishing certain evidence of the multiplication of 

 cells by segmentation, daughter cells, which originate freely in 

 the fluid contents of the parent cell, cause the increase, and by 

 their enlargement the division of the cell-interior by means of 

 septa is brought about. 



Moreover the wall of the cell is not simple, but composed of 

 several cells placed one within the other, which are frequently 

 regenerated from within outwards by the unfolding of the nuclear 

 cell, and each of which cells passes through a course of develop- 

 ment peculiar to itself. 



The involution of the coats of the cell, in the few tissues 

 where it has as yet been actually observed, does not give rise to 



* A translation of these valuable investigations will appear in a future 

 Number of the ' Annals.' 



