922 Br enck ley , — The Development of the Grain of Barley. 
a few hours to a day, according to the age of the grain, and Mann’s fluid 1 
applied for a few hours to two days. 
Entry of Starch. The development of the barley grain has been well 
described by Johannsen, 2 while the mature structure is portrayed by Brown 
and Morris. 3 These authors, however, do not give any detailed account of 
the entry of starch into the grain in its progressive stages. 
The entry of starch into the grain was investigated by means of material 
preserved in acetic alcohol. Hand sections were cut, stained with iodine in 
potassium iodide, washed in water, and mounted in glycerine. 
Four days after flowering very little endosperm could be made out, and 
there were no indications of starch. The pericarp, however, was very thick 
and fleshy, containing a good deal of starch in all its cells, especially in the 
layers near the seed. By the next day the endosperm appeared to be still 
deficient towards the embryo end, though it was fully formed at the other 
end ; but no sign of starch had appeared. Plenty of starch existed in the 
pericarp, though it was only found thickly in the region of the vascular 
bundle. By the sixth day from flowering starch-formation had begun 
at the chalazal end of the grain, but the grains were so small that it 
required an 18 Zeiss ocular and either an AA or DD objective to trace them. 
Most of the grains had been laid down in cells in the middle of the flanks, 
none appearing as yet across the bridge. In some cells the association 
between the starch grain and the nucleus could be made out. A short dis- 
tance from the chalazal end of the grain no trace of starch had yet appeared. 
By the seventh day distinct progress had been made, as starch could be 
discerned for about two-thirds the length of the grain from the chalazal end, 
occurring as scattered grains in the flanks. The cells in which deposition 
first began contained considerably more starch than on the previous day, 
though as yet there was no considerable mass of it, as all the grains remained 
easily discernible and relatively few in each cell. By the day following that 
on which the sections were cut all the colour had disappeared from the 
endosperm starch, though it was retained by the pericarp starch. The 
pericarp at this time was still broad and uninjured throughout the length of 
the grain, with a good deal of starch scattered in the cells, though all the 
grains were easily seen individually. Just round the vascular bundle there 
was a dense mass of starch, especially on the side towards the endosperm. 
By the tenth day from flowering starch infilling was in full swing. The 
embryo was in its early stages of development, and towards the lower 
1 Mann’s fluid : — Water ioo c.c. 
Mercuric Chloride 2.5 grm. 
Picric acid 1 grm. 
40 % Formalin solution 10-15% 
{Vide Mann : Physiological Histology. Oxford, 1902.) 
2 Johannsen, W. : Resume du Compte rendu du Laboratoire de Carlsberg, ii, 1884, p. 3. 
3 Brown, H. T., and Morris, G. H. : Journ. Chem. Soc., vol. lvii, Trans. 1890, pp. 460-6. 
