16 Messrs. Brown and Escombc. On the Depletion of the 



in the endosperm-cells, and this inquiry is the more necessary since 

 we know that even the distal portions of the endosperms of the 

 barley-grain contain a certain amount of a feeble diastase, and in 

 most cases also a distinct amount of a cytobydrolytic enzyme.* 



In the first place we satisfied ourselves that both the amylohydro- 

 lytic and cytohydrolytic enzymes of barley are not appreciably 

 weakened in their respective actions by a saturated aqueous solution 

 of chloroform. f A number of grains of barley were degermed, 

 and, after being softened by a sufficiently long steep in chloroform- 

 water, were placed in the usual manner on a mica-raft, which was 

 floated on water kept fully saturated with chloroform during the whole 

 of the experiment. Under these conditions bacterial growth was. 

 quite inhibited, as was also any autonomous action due to the endo- 

 sperm-cells, but the pre-existent enzymes, on the other hand, were 

 allowed full play to produce any alterations of which they were 

 capable. 



Not even the feeblest action of any kind could ever be detected 

 in the endosperm-tissue placed under these conditions, even after 

 the lapse of several weeks, and we must therefore regard such 

 experiments as fatal to the view that pre-existent enzymes exercise 

 any appreciable influence in bringing about the well-marked and 

 definite changes in the endosperm such as we have described. 



We are thus led to what appears to be the only conceivable expla- 

 nation remaining, that the phenomena are dependent on the meta- 

 bolic activity of some portion of the endosperm itself; and if this is 

 the case, it follows that during normal germination the endosperm is 

 not wholly passive, but takes some share with the embryo in prepar- 

 ing the reserve materials for the use of the young plant. 



It now remains to ascertain how far it is possible to localise the 

 particular part of the endosperm-tissue which is active in producing 

 these changes, an inquiry which resolves itself into an examination 

 of the respective functions of the ' ; alenrone-layer " and amyliferous 

 cells respectively. 



The observations of Tangl,^ and more recently those of Haber- 

 landt, have shown that each of the " aleurone-cells " possesses proto- 

 plasm with the usual reticulation of fine strands, enclosing a well- 

 d^fined nucleus, and presenting all the usual cytological evidences 

 of activity. As far as we are aware, no one who has ever carefully 



* ' Chem. Soc. Journ.,' 1890, p. 507 ; ibid., 1892, p. 362. 



f These facts were determined by estimating the diastatic and cytohydrolytic 

 powers respectively of extracts of the grain made under similar conditions, in the 

 one case with water only, and in the other with a saturated aqueous solution of 

 chloroform. The determinations of diastatic activity were made by Lintner's method, 

 and those of the cytohydrolytic by the times necessary to produce visible action on 

 the cell-membranes of thin sections of the grain immersed in the two liquids. 



J ' Sitzungsber. d. Wiener Akad.,' vol. 102, 1885. 



