178 NATURAL SCIENCE [September 



Now, although Mr Etard has, by virtue of masterly analytical 

 skill, succeeded in separating certain distinct green bodies occurring 

 in the same species, which seem to respond to a definite chemical 

 composition, it is not so clear that the question as to what chloro- 

 phyll itself really is has been finally settled. The grand difficulty 

 is to decide definitely whether chlorophyll is (like carotin) a solid 

 substance in itself and present in such quantity as to allow of its 

 being separated and withdrawn purely and simply from the other 

 constituents of the leaf ; or whether it exists therein in exceedingly 

 minute quantity only (like that of a dye fixed on a vegetable fibre), 

 and inseparable therefrom save by means which bleach and destroy 

 it irrevocably ? It is evident that if the former alternative be 

 accepted, then by simply absorbing the green pigment by animal 

 charcoal from the ' chlorophyll,' it will still retain its physical and 

 chemical characters unchanged ; if the latter be adopted, the same 

 absorption will completely destroy only the colouring matter as such. 



Unfortunately it is absolutely impossible to tackle the question 

 on these grounds or in this fashion, for the simple reason that no 

 solvent at present known extracts chlorophyll, i.e. the pigment, 

 purely and solely from the leaf ; it is invariably conjoined with 

 fats, waxes, resins, etc., and even subsequent exhaustive treatment 

 with a series of different solvents does not eventually effect a com- 

 plete purification. Such being the case, we must rest content with 

 the results and effects of close application and a prolonged experi- 

 ence, feeling assured that in the course of time views and vistas 

 will open, leading to a correct apprehension of the subject. One of 

 these views may now be exploited for the edification of the reader. 



Microscopic observation of the living leaf reveals that the 

 chlorophyll granules are individually independent globules of dense 

 protoplasm without proper walls plunged in the midst of the funda- 

 mental protoplasm and tinged by the green matter, their form and 

 size remaining unaltered when extracted by ether, etc. Protoplasm 

 itself is of course insoluble in the solvents which readily dissolve 

 chlorophyll, but it is always accompanied by fatty matter of free 

 formation which doubtless is one of the products of assimilation. 

 Starch also, although not invariably present, very commonly occurs 

 in these corpuscles ; and Belzung seems to think that its presence is 

 necessary for the formation of the green pigment — an opinion which 

 I am disposed to dispute. In addition, however, to starch and fat, 

 the occurrence of which is sufficiently palpable, it would be absurd 

 to imagine that other bodies are not evolved in quantities more or 

 less minute during the career of the tremendous vital energy exerted 

 by the living protoplasm. Tremendous certainly it must be at the 

 actual moment of its outcome, but perhaps for that very reason 

 essentially frail and subject to degradation and decay. Hence arise 



