67 
winter storms is thet the fibrillle of the rootlets are absolutely 
separated from the cellular layer which envelopes them, and the 
hair-like processes are removed from immediate contact with the 
cells which are to set up the new growth. ‘This is accomplished by 
vibration. If a plant be examined in the summer, the 
rootlets are found terminating in fibrille. If these are carefully 
manipulated, they are seen to be covered with microscopic hairs 
which extend for some distance from the plant. He had traced 
them for some inches in the case of the fibrille of rye-grass. They 
could not be seen by the naked eye; it is probable that they 
extend many feet. They extend by cell growth, and as they extend 
they transmit sap upwards into the radicles and through the flbro 
vascular tissue of the root to the trunk of the tree, but not into the 
bark. This sap in all cases consists at first of water containing 
carbonic acid, albumen, sugar, and gum in solution with the varicus 
salts which are capable of solution and absorption by plant life. A 
powerful capillary attraction is superadded to the endosmosis which 
arises in the cells of the root-hairs, and together they produce the 
vis a tergo upon which the circulation partly depends. 
As soon as the minute hair-like processes on the roots have 
fulfilled their mission, aod the leaves cease to decompose the car- 
bonic acid in the sap, they become useless ; oxygen ceases to be 
discharged, some is used up in the oxidising process by which 
a change of colour is produced in the leaf itself. The winter storms 
then, by swaying the tree backwards and forwards, remove the 
cellular matter which is in close proximity to the rootlets and allow 
a minute rift in the soil, along which the air which is required for 
the new growth can find its way. The floods of spring wash away 
the cellular exuviz, the water carrying down with it carbonic acid 
and ammonia compounds as well as oxgyen ready for use as soon as 
the germ of protoplasm at the extremity of each root-fibre awakes 
from its dormant state. Thus there is cell-growth beneath the soil 
as well as above it, and the more rapid that cell-growth is the more 
rapid will be the growth of the plant. In the case of certain 
cereals, as wheat and oats, the fine hair-like fibres have been traced 
to a depth of from five to six feet from the surface of the ground. 
In the case of rye-grass a felt-like web is formed on the surface of 
the soil which appears able to digest albuminous matter, and 
especially to absorb bioplasm. Chemically there does not appear to 
be any difference between the albumen of plant life and the albumen 
of the blood. They are mutually convertible by the aid of the vital 
power which exists in the fibrille of the plant as well as in the 
digestive organs of the animal, and thus one class of plants are 
able to grow with intense rapidity because the particular pabulum 
which has passed through the cell by an action which they reqnire 
is ready at hand in a state fit for immediate assimilation. These 
