82 Prof. J. Keynolds Green and Mr. H. Jackson. [Mar. 22, 



globoids of the aleurone grains and before any reaction for phosphoric acid is 

 obtainable. The probability of an oxidation of the oil taking place in the 

 early stages of germination has already been pointed out. This is now 

 rendered still more probable by the discovery of an oxidase in the 

 germinating seeds. On mixing a strained and filtered extract of the 

 endosperms with a solution of hydroquinone, the colour of the latter 

 speedily becomes pink and, later, red. The extract gives instantaneously 

 a blue colour with an emulsion of guaiacum, and slowly turns a solution 

 of pyrogallol purple. Boiling the extract destroys the power of setting up 

 these changes. The oxidase adheres very tenaciously to the tissue of the 

 endosperm, and it is very difficult to extract it completely. 



Though the oxidase can be extracted and the extract found to act on such 

 easily oxidisable bodies as those mentioned, no attempt has succeeded in 

 making it oxidise ricinoleic acid outside the plant. This may, however, be 

 due to non-attainment of the conditions which exist in the cells of the 

 endosperms. Though its appearance is suggestive, it has not been proved 

 that it plays a part in the oxidative processes of the fats, if the latter take 

 place. The probability of such oxidative processes is considerable, for, in 

 addition to the considerations just put forward, it should be remembered 

 that one of us has shown that the formation of the acid is dependent upon 

 the access of oxygen. In seeds germinated in its absence, though part of the 

 oil was transformed, no acid soluble in water was formed.* 



The problem is complicated by the fact that the distribution of the lipase, 

 invertase, and oxidase of the germinating seed is practically the same. 



Nutrition of the Embryo. 



The sequence of changes which has, so far, been described, suggests a 

 modification of the views now current as to the mode of utilisation of reserve 

 materials in albuminous seeds. It has been commonly held that the efforts 

 of the parent plant ceases with the deposition of reserve food in or near the 

 embryo, in such a condition as to be easily used. Possibly, also, certainly in 

 some cases, the parent is responsible for the provision of an enzyme to effect 

 the change of the reserve food into a suitable condition for absorption. The 

 utilisation is, however, attributed more or less fully to the embryo. In many 

 cases the latter secretes the enzymes itself, and in others it is the active 

 agent in absorption. The metabolic changes in the endosperm attributable 

 to the parent are held to be more or less independent of each other, and to 

 consist of the enzyme actions only, each enzyme fitting its appropriate food 

 for absorption. 



* GreeD, loc. cit., p. 389. 



