Dr Barry on Fissiparous Generation. 209 



principle, such as mucilage into elaborated sap, or albumen 

 into fibrin, is effected in particular situations by the vital 

 agency of transitory cell-life."* 



11. The foregoing paragraphs (1 — 8) will shew that I go 

 farther. Assimilation of the substance introduced into the 

 parietal nucleus of the cell appears to me to be part of the 

 process which propagates the celt. The reproduction of cells is 

 essentially fissiparous ; and it is a process of assimilation that 

 prepares them for being cleft. 



12. I proceed to state rather more in detail, yet very briefly, 

 the facts on which my opinion rests. 



13. The orifice above mentioned, as contained in a certain 

 part of the cell-wall, represents the situation of a highly pel- 

 lucid substance, originally having little if any colour. This 

 substance exhibits properties remarkable indeed; and as I 

 shall have occasion constantly to refer to it in this memoir, I 

 may be permitted, for the sake of avoiding repetition, provi- 

 sionally to denominate it hyaline^\ a term which seems unob- 

 jectionable, from its being descriptive of the appearance only. 

 This hyaline is primogenital and formative. It appropriates 

 to itself new matter, then divides and subdivides into globules, 

 each of which passes through changes of the same kind. Un- 

 der certain circumstances it exhibits a contractile power, and 

 performs the motions called molecular. It is this hyaline 

 which is the seat of fecundation in the ovum, and it is present 

 in the large extremity of the spermatozoon ; it is by successive 

 divisions of this substance that properties descend from cell 

 to cell, new properties being continually acquired as new in- 

 fluences are applied, but the original constitution of the hyaline 

 not being lost. The main purpose for which cells are formed 

 is to reproduce the hyaline ; and this they do by efi^ecting the 

 assimilation which prepares it to divide. The division of the 

 hyaline is thus the essential part of fissiparous generation. 



14. Schleiden was the first to direct attention to what I 

 believe to have been a globule of hyaline in his " cytoblast ;" 

 and its various appearances he has faithfullv described. But 



• British and Foreign Medical Review, No. XXIX., Jan. 1. 1843, p. 27J, 

 t A term suggested to n^e by Professor Owen, 



