44 THWAITES'S THEORY. [BOOK i. 



protect, locate or isolate, the matter it contains, and that any 

 vitality it possesses is derived from the presence within it of its 

 endochrome. There are, however," he proceeds, " a few phe- 

 nomena which at first sight would appear to militate against 

 the opinion I have advanced ; I mean the contractility of 

 certain membranes and the movement of ciliary appendages 

 belonging to others. It is very certain, that during the vital 

 processes which are going on in the interior of the cell, 

 considerable chemical changes take place ; and these must of 

 necessity give rise to an elimination of electrical currents. 

 The presence of such currents would, I think, be sufficient 

 to account for the rhythmical movement of cilise, as well as 

 for the contraction of membranes of certain mechanical 

 structure. 



" I would ask whether these electrical currents may not 

 give rise to the formation of the mucus surrounding the cell, 

 and determine its character and extent ; whether, too, the 

 production of cell-membrane may not occur under a similar 

 influence ; and whether this would, not be the easiest solu- 

 tion of the problem of how the cell is increased in size ? viz. 

 that a formation of cell-membrane takes place within the 

 range of these currents, whilst absorption occurs within or 

 without it. On this principle, too, we can better understand 

 the process of the fissiparous division of cells; the endo- 

 chrome becoming divided into two portions, two centres of 

 electrical force are originated, and each of these giving rise 

 to a set of currents, two cell-membranes are produced instead 

 of the original one. The frequent occurrence of nests of 

 regular crystals (not sand) in the substance of the mucous 

 envelopes of such freshwater genera as Batrachospermum, 

 Chsetophora, and Monormia, would seem to aiford positive 

 proof that electrical currents exist there. 



" These views, if correct, would, of course, apply to animal 

 as well as vegetable organisms, and we should be under 

 the necessity of considering the entire membranous or solid 

 portion of the animal as of a subordinate character to the 

 fluids contained in its cells, and merely as an instrument 

 acting in prompt obedience and conformity to the changes 

 taking place in these fluids. 



