360 HOW CROPS GROW. 
The coats of the dry seed when put into the moist soil 
imbibe this liquid which follows the cell-walls, from cell 
to cell, until these membranes are saturated and swollen. 
At the same time these membranes occasion or permit os- 
mose into the cell-cavities, which, dry before, become dis- 
tended with liquid. The soluble contents of the cells or 
the soluble results of the transtormation of their organized 
matters, diffuse from cell to cell in their passage to the ex- 
panding embryo. 
The quantity of water imbibed by the air-dry seed commonly amounts 
to 50 and may exceed 100 percent. R. Hoffmann has made observations 
on this subject, (Vs. S¢., VII, p. 50.) The absorption was usually com- 
plete in 48 or 72 hours, and was as follows in case of certain agricultural 
plants :— 
Per cent. Per cent. 
VINTEC cic ararcratclarstete avatars 8.0 Oats. .5..c ccc eeeeeeeee 59.8 
Millet. ci. 44% aehier o 25.0 Hemp ... 2.0 tive dehneen 60.0 
Maize. ic. isis's oo% bib iejoie rote 44.0 Kidney Bean ......... 96.1 
WRONG re oe aicc codeiasie © 45.5 Horse Bean... ....+00.-1040 
SUCK WHERE cicsc lsc nis.c s1e0/2 46.8 PGA 22.0 a.» emis sees 106.8 
IBRITEY sis cic oc o'e te e.ote-0 « a'0s 48.2 CloVer.i.cincike heer 117.5 
GET 22 hie eicchis chee b/e%"s 51.0 Beet i:6% cule nieente weed eOla 
LG AEA BADE peisiviceissONe 8, White Clover-<.caecees 126.7 
Root-Action.—Absorption at the roots is unquestiona- 
bly an osmotic action exercised by the membrane that 
bounds the young rootlets and root-hairs externally. In 
principle it does not differ from the absorption of water 
by the seed. The mode in which it occasions the surpris- 
ing phenomena of bleeding or rapid flow of sap from a 
wound on the trunk or larger roots is doubtless essentially 
as Hofmeister first elucidated by experiment. 
This flow proceeds in the ducts and intercommunicating 
wood-cells. Between these and the soil intervenes loose 
cel]-tissue surrounded by a compacter epidermis. Osmose 
takes place in the epidermis with such energy as not only 
to distend to its utmost the cell-tissue, but to cause the 
water of the cells to filter through their walls, and thus 
gain access to the ducts, The latter are formed in young 
