Germination of the Seed of the Castor-oil Plant. 389 



noted, too, that, though starch did not normally appear in the germi- 

 nating endosperm, under the condition of non-removal of the pro- 

 ducts of the decompositions, it did appear in the cells in the form of 

 small grains, though not till after several days. Van Tieghera also 

 observed that the progress of the decompositions could be arrested, 

 and the endosperm made to re-assume a quiescent condition, and that 

 then the aleurone grains again became formed, though in less quan- 

 tity than before. 



To a large extent my observations confirm these of Van Tieghem, 

 though I did not continue the experiment for so long a time. Some 

 endosperms prepared by removal of the embryo by the knife were 

 exposed on damp sand to a temperature of 38 C. in an incubator. 

 Others were placed with them after removal of the plumule and 

 radicle only, leaving the large cotyledons lying on the endosperms 

 undisturbed. 



After three days, the former ones contained a little unaltered oil, 

 a good deal of fatty acid, a trace of crystallisable acid, and a little 

 sugar. The latter set were much more swollen than the former, 

 and contained a larger amount of crystallisable acid ; the other con- 

 stituents being much the same. 



In a furth'er experiment endosperms, prepared similarly, were 

 attached to the under side of the cork of a small wide-mouthed 

 bottle containing a little water, and were thus cut off from the access 

 of free oxygen. They were then placed in the incubator at 38 C. 

 The change in bulk of these was very slight during the time 

 (fourteen days) during which the experiment lasted; and when 

 examined their contents were found to be much less affected. Part 

 of the oil was transformed, about one-fifth being replaced by fatty 

 acid, while no sugar and no acid soluble in water could be extracted 

 from them. 



I cannot confirm Van Tieghem's observation as to the occurrence of 

 starch in the cells under these abnormal conditions ; but my experi- 

 ment, made under the same conditions as his, probably was not con- 

 ducted for a period long enough to secure its formation. Gris* 

 states that when he found starch grains formed in the endosperm 

 cells it was not until their first contents had been completely absorbed. 



Histological investigation of the endosperms, both when germi- 

 nated normally and when the embryo had been removed, indicates 

 that the changes are not set up by the latter. The decomposition 

 of the oil does not in either case take place regularly on the side 

 nearest to the cotyledons, but cells throughout the whole endosperm 

 are affected simultaneously. 



The same conclusion is pointed to by the experiments already 

 quoted as to the antecedent condition of the ferment. The ground 



* Gris, op. cit. 



