W. E. BllENCIILEY AND A. D. HaLL 



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cation stage. Evidently tlie end process of ripening is accompanied by 

 a change from non-protein to protein nitrogenous compounds. 



General outline of the process of viigration. It is now possible to 

 summarise the whole process of the migration of the reserve materials 

 into the wheat grain. The first samples were taken about ten days after 

 flowering ; at this time the endosperm is just formed, but the grain is 

 in the main made up of the active living tissues constituting the pericarp. 

 The figures for July 14th in Plate XV (taken from W. E. Brenchley, 

 loc. cit.) show the structure of the grain at this stage. During the 



grams 

 220 



Plot 3 

 Plot 10 



3 6 12 15 18 21 24 27 30 33 36 39 days 



Fig. 14. Maltose produced per 1000 grains, 1907. The dark line shows the mean curve 

 of the three plots, placed two squares too low for the sake of clearness. 



next twelve days the endosperm is beginning to fill, as shown by the 

 appearance of starch grains in the cells, until by the end of the period 

 starch is to be found throughout the endosperm. But the most 

 characteristic feature of this stage is the depletion of the cells in the 

 pericarp and their crushing together, until they become nothing more 

 than membranes containing no living cells; the end of this stage being 

 shown by the second set of figures in the plate. It is during this 

 period that the nitrogen percentage of the grain is falling rapidly ; the 

 cells of the pericarp when active evidently possess a comparatively high 



