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the wood of large trees, have their thick cell-walls formed largely 
of lignin, so that the indigestibility of wood-tissue is apparent. 
It is true that digestion, even of wood, is not wholly impossible, 
For experimental purposes, wood sawdust has been soaked, 
baked and ground, and these operations successively repeated, 
until a large part of it has been converted into a digestible starch- 
like substance. Yet the idea of the general consumption of cork 
or wood is ludicrous. Ina wild state this ‘‘ woody ” condition 
of our vegetable foods is far greater than under cultivation, and 
in fact one of the prime objects of cultivation is to render tough 
vegetables tender. Housekeepers are well-acquainted with the 
tough or stringy character of vegetables which have been im- 
perfectly cultivated. While we speak of this in common lan- 
guage as ‘‘improving their tenderness’’ and are apt to think of 
it only as to its effects upon palatibility, it is in reality in the 
highest degree efficacious in increasing digestibility and net nutri- 
tive value— and all this, though it strikes the ordinary individual 
only as a change in the general characters of the bulk or mass, 
relates really to the structure and composition of the cell-wall, 
a condition which is perfectly apparent and calculable by micro- 
scopical methods of inspection. Hence the importance to those 
who have any intention of seriously considering vegetarianism of 
being trained to microscopical, ag well as to chemical methods of 
research, 
We can only appreciate at its full value the practical importance 
of these changes in the cell-wall when we know of the radical 
modifications which they render necessary in the computation of 
the feeding value above referred to. ose reference works 
which have taken account only of the chemical composition of 
the foods of which they treat have been found in practice to 
possess relatively little value. It long since became apparent 
that much of the nutrient matter thus estimated was entirely un- 
available to the systems of the animals consuming them, as they 
passed undigested out of the body, in the form of waste. It then 
became necessary to institute a series of experiments entirely new 
in kind, and necessitating a degree of patience, attention and 
vigilance previously unknown in this line of research. The 
