Adipocelluloses and Cutocelluloses 237 



more so for the chemist, who deals with the cell- substance. 

 Another phase or aspect of the vital process, of which also the 

 science of to-day gives a very slender account, is that of the 

 organic connection of the vast assemblage of cells which con- 

 stitute a vegetable organism more particularly the subordina- 

 tion of each unit to the general life- history of the plant, and the 

 extraordinary complex of adjustments which this involves. 

 These, again, are hardly problems for the chemist, save, perhaps, 

 in regard to the organic relationship of the cell-wall to the 

 protoplasm by which it is formed. 1 The most striking general 

 feature of the cellulosic group is that they are non-nitrogenous \ * 

 it might be reasoned, therefore, that they are, from the first, 

 excreta, and never live in the full sense of the word. Without 

 pushing these considerations into an argument of doubtful 

 value, we may conclude that from the moment of origin the 

 history of the cellulose group is one of progressive withdrawal 

 from the region of the vital processes proper, and that to again 

 enter that region they must undergo a process of proximate 

 resolution as a result of action from without. This reabsorption 



1 The views obtaining on this point are summed up by Goodale at 

 p. 218 of < Physiological Botany,' under the heading ' The Relations of 

 the Cell Wall to Protoplasm.' They are, in the main, two : (i) The 

 cell wall is formed, by the solidification upon the exterior of a protoplasmic 

 mass, of matters previously dissolved in it, the pellicle thus formed being 

 regarded as an excretion or secretion. This view is held by Hofmeister 

 (Pflanzenzelle) and Sachs. (2) The cell wall is directly produced by 

 conversion of the outer film of protoplasm into cellulose, with which other 

 groups may be mixed or combined (Schmitz, Sitz. d. Niederrh. Ges. Bonn, 

 1880). This conclusion is based upon the observation that the volume of 

 protoplasm in a cell decrease $ pari pqssu with increase of the cell wall, and 

 upon the phenomena which attend thickening of the cell wall. 



The distinction between these theories, however, is rather morphological 

 than chemical ; and the view expressed in the text may be taken as con- 

 sistent with either theory of the actual mode of formation of the cell wall. 



2 We are not aware of any specific proof of the assumption that the 

 celluloses are ab initio non-nitrogenous. It is possible that they contain 

 NH.j residues in the earlier phases of growth. 



