Conditions of its Production in the Plant. 321 



and there, separated spontaneously, as it were, from the chlo- 

 rophyll-bodies. 



It is therefore certain, even from our present experience, 

 that the oleaginous substance which is a constituent of every 

 chlorophyll-grain can be separated therefrom by various 

 means. It would almost appear that this can be effected 

 purely mechanically by displacement and disturbed adhesion. 



One of the simplest means of separation is the application 

 of moist heat. If green tissues be heated with water, or dis- 

 tilled with aqueous vapour, drops of an oleaginous substance 

 separate from the fundamental substance of the chlorophyll- 

 bodies. The phenomenon is analogous to that which Briosi 

 produced in the chlorophyll-bodies of the Musacea3 by treat- 

 ment with cold water. In his fine memoir on this subject * 

 he assumes (and in this later observers have followed him) 

 that the normal occurrence of oil in the chlorophyll-bodies of 

 the Musacea?, is an exceptional case, forming as it were a sub- 

 stitute for deficient starch. But, as I shall here show, the 

 occurrence of oil in the chlorophyll-bodies of plants is quite a 

 general phenomenon and certainly not directly dependent on 

 the presence or absence of starch-enclosures ; only, it would 

 appear, the escape of the oil from the chlorophyll-bodies does 

 not take place in most plants except by treatment with water 

 of higher temperature. 



In many plants a heat of 50° C. ( = 122° F.) suffices; and 

 at this temperature any starch-enclosures that may be present 

 do not swell up. Other plants require higher temperatures, 

 when, in consequence of the swelling of the starch-enclosures 

 or the bursting of the whole chlorophyll-grain, the compre- 

 hension of the process may be rendered more difficult by 

 collateral circumstances. The phenomenon is also easily 

 called forth if the tissues are exposed for from ten to fifteen 

 minutes or longer to the vapours of boiling water. 



In all cases there are, after this treatment, as already indi- 

 cated, at the periphery of the chlorophyll-bodies, some smaller 

 or larger oil-drops, which clearly have issued from the chloro- 

 phyll-bodies under the action of the warm water or of the hot 

 vapour. 



The chlorophyll-bodies themselves at the same time acquire 

 the nature of hollow bodies, which may put on a different 

 appearance in different plants according to the temperature 

 employed and the duration of the action. They either con- 

 stitute spongy porous masses, or form hollow trabecular 

 networks, or, lastly (especially when strong swelling with 



* Bot. Zeitimg, 1873, p. 529. 



