STRUCTURE.] THWAITES's THEORY. 39 



cases, deduce a safe analogy applicable to all." (Ray Reports, 

 1846.) 



Q. Cells are formed by Cytoblasts generated amidst mucus 

 or protoplasm, by the action of the Cy to blast and certain elec- 

 trical currents connected with it, of which forces the Cytoblast 

 is the centre. The electrical currents are caused by chemical 

 changes, arising from the vital processes, which go on amidst 

 the endochrome or contents of the cell. In this point of view 

 the cell-membrane is regarded as of no further importance to 

 the cell-contents or endochrome than as an external guard to 

 them ; the vital processes and the production of the mem- 

 brane itself being carried on by their contents, in which 

 alone vitality resides. " If/' says Mr. Thwaites, (< a decaying 

 vegetable organism is brought before us, in which nothing 

 remains of the former structure but the cell-walls, it is 

 difficult to conceive that this skeleton, as it were, has per- 

 formed an important part in the vital processes of the plant, 

 that it has been an important agent in the chemical changes 

 which had been going on during the processes of secretion, 

 assimilation, &c. in fact, that it has been any other than a 

 mere skeleton for the support of the important parts of the 

 organism" a shell as it were to protect them. This re- 

 markable theory is of so much importance that, in justice 

 to its author, his views must be given as nearly as possible 

 in his own words. The original, with all the details which 

 I have been obliged to omit, will be found in the Annals of 

 Natural History, vol. xviii. p. 15. 



" There cannot be a more satisfactory way of showing the 

 subordinate character of the cell-membrane than by exhibiting 

 a perfect living organism in which it does not exist, and there 

 are some plants, belonging to the family Oscillatorieae, in one 

 of which (a species of Spirulina) there appears to be no real 

 membrane the plant consisting of a mucous matrix, out of 

 which, when the species is mature, emerge oscillating spiral 

 filaments, which from their exhibiting no trace of cell-mem- 

 brane, or even of any division, by septa, into separate portions, 

 and from the rapidity with which they become decomposed, 

 I believe to be continuous masses of endochrome held together 

 by mucus. Another species to which I would direct attention 



