352 Kirkwoop AND GIES: CHEMICAL STUDIES 
pendent career. Neither the husk nor the shell appears to serve 
any other than passive mechanical function, and only the constitu- 
ents of the endosperm and milk, so far as the nut is concerned, 
nourish the young plant before it finds in the soil the elements 
provided there in abundance for its growth to maturity.* 
In our microscopic studies, particularly of the cotyledon, 
pieces of the fresh part were “fixed” in a mixture of glacial 
acetic acid (1%) and 70% alcohol (2%). After remaining in this 
fluid for a few hours the pieces were transferred to 70% alcohol 
and later to 85% alcohol, in which they were kept. Sections were 
cut with a razor and mounted in glycerin. Treated with iodine, 
such sections of the cotyledon showed an abundance of starch in 
all cells except those of the outermost layer or epidermis. This 
outer layer stained yellow with iodine. That it contained an abund- 
ance of oil was shown by its deep black reaction with osmic acid. 
Large globules of oil are, however, distinctly visible in the epidermis 
under the microscope without the aid of osmic acid. Oil may 
also be found in the subepidermal layers, but it rapidly diminishes 
in quantity as the distance from the outside increases and as the 
starchy deposit accumulates. Needle-like crystals may be very 
readily found in the epidermal cells. These resemble crystals of 
tripalmitin, but the fact that so much oil appears in globules, and 
that the breaking down of fats must occur to a large extent ™ 
these cells, would suggest that they are palmitic acid rather than 
the fat itself. 
The above facts make it appear that the starch is formed indi- 
rectly at least from the oil.t See references under enzy mes, 
pages 345 and 358. 
See pl. 19 for drawings of parts mentioned above. 
CHEMICAL CHANGES.—The following summary gives briefly 
the effects of germination on the individual nuts examined : 
I. Not Analyzed.—aA., Development had proceeded for nearly 
six months. The plumule protruded six inches above the husk. 
Roots had developed through the husk—two were about a quarter 
of an inch in diameter. The stem was very thick at the « root 
* Note references on page 357 to the functions of the husk in holding walet 
possibly furnishing nutrient matter in its decay. 
t Ebermayer : Physiologische Chemie der Pflanzen, 347. 1882. 
