Conditions of its Production in the Plant. 327 



any rate does not lose, in sharpness. If the chlorophyll- 

 bodies contain but little starch or none at all, the tissues may 

 without injury or even with advantage be boiled for a short 

 time (about half an hour) in water before their treatment 

 with hydrochloric acid. In many cases the reverse process 

 (treatment first with hydrochloric acid and then the action of 

 aqueous vapour) is more efficacious. 



While by this mode of treatment the oil issues from the 

 chlorophyll-grains, the latter appear in all plants as if dif- 

 ferentiated into a denser and a softer mass, and acquire a 

 sponge-like aspect. The places of the soft substance which 

 form the meshes of a net of which the denser substance con- 

 sists, soon appear as true cavities from which the oil has 

 escaped. In this way the whole grain finally appears to be 

 perforated like a sieve , producing nearly the characteristic 

 impression of a regular sieve-plate ; or in those cases in 

 which the sieve-like perforation does not appear very sharply, 

 it shows a spongy-porous texture which reminds one of the 

 differentiations of substance which occur in many states of 

 cell-nuclei. 



The constancy and uniformity with which this spongy- 

 porous structure is displayed by careful treatment in all 

 chlorophyll-bodies proves it to be their normal structure. 

 The solid constituents form the framework ; the oil and the 

 chlorophyll-colouring-matter dissolved therein saturate it and 

 fill up its pores. 



It is impossible that this concordant structure and this defi- 

 nite form of the solid constituents should always occur uni- 

 formly in all chlorophyll-bodies, if this differentiation and 

 distribution of the solid and fluid constituents were not nor- 

 mally expressed in the chlorophyll-grain. It is only complete 

 saturation with oil that causes the latter to appear homogene- 

 ous in the normal state ; and the solution of the chlorophyll- 

 colouring-matter in the oil is at the same time the cause of the 

 absorption-spectrum of the chlorophyll-bodies and of green 

 leaves appearing displaced towards the red end, in opposition to 

 the absorption-spectum of alcoholic and ethereal solutions of 

 chlorophyll. For the oil and the hypochlorin, as is shown 

 by every observation under the microscope, are powerful sol- 

 vents of the chlorophyll-colouring-matter, and ,at the same 

 time (like other solvents also) determine the tone of colour 

 and the absorption-spectrum of the solution of chlorophyll ; 

 and upon this also depend the different colour-phenomena 

 which may be observed under the microscope during the sepa- 

 ration of the constituents of the chlorophyll-grain, in the 

 escaping drops and the residuary solid framework. 



