12 Messrs. Brown and Escombe. On the Depletion of the 



place, the cell-contents become hyaline in appearance, owing to the 

 protoplasmic matrix losing its granularity and acquiring a refrac- 

 tive power approximating to that of the embedded starch-granules. 

 Later on these hyaline portions imbibe water and swell up enor- 

 mously, ultimately becoming very elastic and ductile, and capable of 

 extension into sticky, stringy masses, very similar in appearance to 

 the gluten of the wheat-endosperm. We shall in future refer to this 

 change as " gluteii-forination." At the same time the cell-membrane 

 of the peripheral starch-cells swells up considerably, and as the 

 action progresses the cell-walls undergo disintegration, with all the 

 indications of cytohydrolysis as described by Brown and Morris. 



It is to this cytohydrolysis that the separation of the "aleuroiie-. 

 layer" is due, and the disintegration due to this cause proceeds 

 centripetally into the endosperm and extends round the periphery 

 nearly to the ventral fold, whilst it advances more rapidly in a 

 distal direction on the dorsal side. The extent to which this cyto- 

 hydrolysis has proceeded is always evidenced megascopically by the 

 reduction of the endosperm-contents to a " mealy " consistency, but 

 even after the lapse of seven or eight days the actual amount of 

 depletion is small, as long as micro-organisms are absent, or present 

 only in comparatively small numbers. If, however, as is frequently 

 the case, masses of Bacteriacece in the zooglcea-state attach them- 

 selves to the mutilated surface of the endosperm, a very distinct 

 removal of some of the endosperm-contents may take place. 



The erosion of the starch-granules is generally not very pronounced 

 under these conditions, but when it does occur it always commences 

 at the same point as the cytohydrolysis, that is, on the dorsal side, 

 at the angle of intersection of the " aleurone-layer " and the 

 ''depleted layer," and extends distally just as does the cytohydro - 

 lyfcic action. 



The starch-erosion produced in this manner under the "aleurone- 

 layer" is, in the main, very different in character from that observed 

 immediately under the scutellum of a grain germinating normally 

 with its embryo attached. Whilst in the latter case the action com- 

 mences by the formation of numerous minute " pits," this pre- 

 liminary pitting is rarely observable in the eroded granules lying 

 under the "aleurone-layer," which show the production of large 

 rifts, and a general concentric dissolution of the various layers. We 

 shall in future refer to these different modes of attack on the starch- 

 cells differing in general appearance from the more deeply seated cells. They are 

 smaller, are packed with far smaller starch-granules, and the proportion of starch - 

 granules to proteinic contents is less. These peripheral cells constitute the youngest 

 part of the starchy endosperm, and may be regarded as haying been arrested in 

 their development by the falling off in the supply of formative material at the 

 j)criod of maturation. 



