Coinpusitiun and Nutritive Vahir. of Striae. 
woody suhst;incos — " incrusting matter," as tlicj are called by 
vegetable physiologists — constitute the true wood or woody fibre of 
plants. In their composition th(>y closely resemble cellulose, 
which is more abundant in young plants tlian in those of more 
advanced growth. The older and harder the plant, the more woody 
or incrusting matter it contains. In green herbage, the insoluble 
residue which is obtained by the above-mentioned treatment 
chiefly consists of cellulose or cellular fibre; whilst in fully ma- 
tured and over-ripe herbs, this insoluble residue principally con- 
sists of incrusting matter or true wood. In intermediate stages 
between a green, succulent condition and a dry, hard, fully 
matured stage of growth, we obtain variable mixtures of cellulose 
and woody fibre. The same process, it will be noticed, which 
is employed for preparing wpody fibre, likewise furnishes cellu- 
lose. Unfortunately we possess no means of separating the two 
from each other, and hence the chemical processes by which the 
woody and cellular fibre in plants is determinetl in our labora- 
tories are not calculated to give us more than at the best a very 
crude idea of the true character of the insoluble matter which 
constitutes the bulk of straw. No difficulty is experienced in 
determining with precision the amount of starch or sugar in a 
plant, but when we attempt to ascertain in two or three separate 
portions the amount of woody fibre in each, it is next to impos- 
sible to obtain corresponding results. But although we speak 
of cellulose and of woody fibre as of two separate and distin- 
guishable substances which exist in plants under conditions as 
variable in texture and other physical peculiarities as in their 
physiological effect upon the animal, tlie chemist is not in a 
position to distinguish the one from the other by means of 
analysis ; and it should be remembered that the physical and 
chemical properties and general character of many organic 
bodies are often extremely different, whilst their chemical com- 
position is precisely the same. The mere composition of cellu- 
lose or woody fibre, therefore, does not afford a sufficient insight 
into their true character, and leaves altogether untouched the 
question whether these substances are digestible or not. 
As long as we are unacquainted with more perfect analytical 
methods, we cannot expect to ascertain by analysis whether 
cellular and woody fibre is digestible, wholly or in part, and to 
what extent. Here, as in so many other matters which have 
scarcely been touched upon by scientific men, the agriculturist 
must be guided by his own experience, and not by the rash 
counsels and exaggerated statements of theorists, who are income 
petent to form a sober and unbiassed opinion on a moot 
question. We know, indeed, that the condition of the woody 
