If a piece of bark and cortex are torn off, the occlusion takes longer, because the tissues have to creep over the exposed area of wood; and the same is true of a transverse cut severing the branch, as may be seen in any properly pruned tree.
Such frost-cracks, sun-cracks, &c., may then be slowly healed over by callus, but if the conditions for necrosis recur the crack may be again opened, or if Fungi, &c., interfere with occlusion, the healing is prevented; in such cases the local necrosis may give rise to cankers.
Chem., 18 95, 1 7, p. i), from the standpoint of the phase rule, do not favour this view, Hoitsema being of the opinion that the occlusion of hydrogen by palladium is a process of continuous absorption.
The first effect of fertilization is the occlusion of the trichogyne from the fertilized carpogonium.
It seems fairly established that when the preliminary heating process of fermentation is drawing to a close, the cotton, hay, &c., having been converted into a highly porous friable and combustible mass, may then ignite in certain circumstances by the occlusion of oxygen, just as ignition is induced by finely divided metals.