418 M. H. V. Mohl on the Structure of Chlorophyll. 



are formed one, or more rarely two large vesicles, which break 

 through the outer grccu layer. Sometimes the formatiou of a 

 single lai'ge vesicle is replaced, in a larger or smaller part of the 

 grain, by that of a large number of small vacuoles, so that the 

 substance of the grain is converted into a frothy mass. No 

 trace of an outer membrane can be detected, consequently I can- 

 not regard as appropriate Hofmeister's application of the term 

 chlorophyll-utricle to this peculiar structure (Yergleich. Unter- 

 such. hoh. Kryptog. p. 3). 



Notwithstanding, therefore, that the anatomical conditions of 

 the chlorojihyll of Anthocerus differ essentially from those exist- 

 ing in Zi/f/nemn, the green-coloured masses of the two plants 

 correspond exactly in regard to the character of their substance 

 and their reaction with water. Hence it seems to follow that all 

 that is requisite for the formation of chlorophyll is, that the 

 green colouring matter be formed in a cell and enter into com- 

 bination with a mass of proteine substance, be the latter what it 

 may ; in any case it is evident that there does not exist any 

 detinite elementary organ, comparable in its organization to the 

 cell, imiformly distributed throughout all plants possessing chlo- 

 rophyll, and especially charged with the formation of this sub- 

 stance. The agreement in the properties of the gieen-coloured 

 substance of two structures so different as the chlorophyll- masses 

 of Zygnema and Anthoceros, leads readily to the conjecture that 

 these properties, the different behaviour of the outer green, 

 and internal substance to water, depend less upon peculiarities 

 in the organization (for, as above remarked, no trace of definite 

 structure is visible), than upon the deposition of the green 

 colouring matter, of resinous character and combined with wax. 

 The hypothesis is not far-fetched, that we must regard the dif- 

 ferent behaviour of the outer and inner substance of the chlo- 

 rophyll-mass, the greater consistence of the former and the 

 violent expansion of the latter in water, as simple consequences 

 of the proteine substance being permeated principally or solely 

 in its outer layers by these foreign substances, insoluble in 

 water ; — or, at least, that this difference, if dependent upon an 

 unequal consistence of the different layers of the protein ous 

 foundation of the chlorophyll-mass, is essentially heightened by 

 that circumstance. 



If we turn to the usual form in which chlorophyll occurs, to 

 that of isolated grains, we find that the position of the latter in 

 the cells is not always the same. They are never found swim- 

 ming freely in the cell-sap, but always stand in connexion with 

 the protoplasm contained in the cell. In the great majority of 

 cases they are applied upon the cell-wall ; under these circum- 

 stances, we may detect by careful observation, if not in all, yet 



