MICROSCOPICAL SEPARATION OF WHEAT AND RYE-MEAL. 193 
MICROSCOPICAL SEPARATION OF WHEAT 
AND RYE-MEAL* 
WITTMACK records the following observations on the micro- 
e scopical distinctions between wheat-meal and rye-meal. The 
amount of starch gives no certain character, and the size of the 
starch-grains is not in itself sufficient ; the maximum size of the 
starch-grains of rye is 42-52 mu; of wheat 28-35 p. Better 
characters are obtained from the grains themselves. 
The denseness of the pitting in the transverse cells of wheat 
gives them a chaplet-like appearance. The shell or pericarp is 
often difficult to meet with in the finer kinds of meal. 
Wheat. Rye. 
|e ia 
Skin, average thickness te 43-50 31-40 
Epidermal cells of the skin or pericarp—length| 116-160 136-400 
An % i breadth 20-28 26-62 
porous pitting very close less close 
Sub- -epidermal transverse- cells—length are 114-192 72-90 
oH nie breadth eat 14-17 1I-14 
55 ne thickness of walls 5°8-8°7 3°3-5'0 
ae very dense less dense, 
rE 2? Boe "| (and conspicuous} inconspicuous 
Starch-cells—average larger diameter sae 56-72 40-64 
shorter diameter Ys 32-40 24-40 
Iso- diametrical starch-cells—diameter sigs 40-48 32-36 
Good characters are also obtained from the hairs. Before 
grinding, both ends are removed from the grain ; the embryo-end 
on account of the oil which it contains; the opposite apex on 
account of its hairs; but a few hairs are still to be found in the 
meal, which give the following characteristics :— 
Wheat. Rye. 
[v2 [pe 
Length of hairs ae Boe 120-742 50-420 
Diameter of the largest ae 15-21 Q-17 
EF at the bulbous base. 28 23 
5 of the smallest... 9-10 8 
55 at the bulbous base. 14 II-I4 
Thickness of wall of the hair.. 7 3-4 
Breadth of cell-cavity ...| 1*4-2 (rarely 5) 7 
Wheat has therefore thick-walled hairs with narrow cell-cavity ; 
rye thin-walled hairs with wide cell-cavity. 
V. Bertholdt+ confirms in the main Wittmack’s statement. He 
* SB. Bot. Ver. Prov. Brandenburg, xxiv. (1882). See Bot. Centralbl., xiii. 
(1882) p. 91. 
' + Zeitschr. f. Landwirthsch. Gew., &c., 1883, pp. 1-3. See Bot. Centralbl, 
xiv. (1883) p. 247. 
