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president’s address. 
amount of protoplasm, hut it gradually becomes pushed aside by 
the expansion of the vacuoles so that it ultimately forms a lining 
of the whole interior of the cell wall. The vacuoles contain the 
cell sap and also act as reservoirs for the storage of reserve material. 
The embryo plant begins its life by the division of the oospore 
into two, these again into four, and so on, so that by this continued 
process of cell division the whole structure of the plant is gradually 
evolved. Several cells united together form tubes whose walls 
become thickened by deposit of ligneous matter and these of 
different kinds aggregated together form the various tissues. 
In order that a plant may transmit its specific characteristics 
from generation to generation, it is necessary that in the division 
of the protoplast, according to Pieffer and others, every organ it 
contains should divide, each of which by the addition of new 
growth then becomes complete again. What the limit of this 
division is, it is impossible to say. It can only be supposed that 
it extends to the minutest particle of granular matter, for there is 
no doubt that every such particle possesses some physiological 
quality of its own which it exercises in a way for some useful 
purpose of the plant. 
There is an important difference between the development of the 
animal and that of the vegetable. In the animal, certain cells are 
differentiated for the formation of different structures, such as 
bone, muscle, nerves, &c., and all these in their multiplication and 
growth retain the same individuality during the life of the animal. 
In the seedling plant all the cells are of the same kind, but accord- 
ing to the requirements of growth, cells become differentiated to 
form, say, a papilla from which it may be, a leaf or a shoot may 
arise, or the peduncle of a flower, a prickle or a single cell to 
form a hair. It is this wonderful physiological attribute of the 
vegetable cell that gives to the plant, other than the conifers, 
its immortal life. An example of this differentiation of cell 
growth is shown in stool shoots where, when a trunk is divided, 
the cambium cells instead of forming wood and bast which they 
normally do, form a callus from which will spring a shoot, that 
in time will produce branches, and ultimately flowers, and seeds; 
