334 REPORT—1852. 
A glance at the Tables as a whole must show, that in all comparable cases 
there is much more of uniformity of amount in the total columns of xon-nitro- 
genous than in those of nitrogenous substance, both as to the quantities con- 
sumed éo a given weight of animal within a given time, and to those required 
to produce a given weight of increase. The deviations from this general 
regularity in the amount of non-nitrogenous substance consumed under equal 
circumstances, are indeed, in most cases such, that when examined into they 
tend the more clearly to show, that the uniformity would be considerably 
more strict if the amounts only of the really available respiratory and fat-. 
forming constituents could have been represented, instead of, as in the case 
of these Tables, that of the gross or total non-nitrogenous substance consumed. 
For, in reading the actual figures of the Tables, allowance has to be made 
both for those of the non-nitrogenous constituents of the food which would 
probably become at once effete, and also for the different respiratory and fat- 
forming capacities of the portions of them which are digestible and available 
for the purposes of the animal ceconomy. It must further be remembered, 
that even after all due allowance has been made for the sources of discre- 
pancy just referred to, the amounts which we may suppose to be so corrected 
must still cover all variations, whether arising from differences of external 
circumstances—from individual peculiarities in the animals themselves—from 
the different amounts stored up in them according to the adaptation of the 
respective foods—as well as from the many other uncontrollable circum. 
stances which must always interfere with any attempts to bring within the 
range of accurate numerical measurement the results of those processes in 
which the subtle principle of animal life exerts itsinfluence. Bearing, then, 
all those points in mind which must tend to modify the true indications of 
the actual figures in the Tables, it appears to us, that the coincidences in 
the amounts of available respiratory and fat-forming constituents consumed 
by a given weight of animal, under equal circumstances, within a given time, 
and also in those required under equal circumstances to produce a given 
amount of increase in weight, must be admitted to be much more striking 
and conclusive than @ priori we could have expected to find them. With 
this general uniformity, however, as to the amounts of mon-nitrogenous 
substance consumed under given circumstances, or for a given result, those 
of the nitrogenous constituents are found to vary, under the same circum- 
stances, in the proportion of from 1 to 2 or 3. 
In illustration of our statements let us examine the Tables for a moment 
somewhat more in detail. 
In Table IV. we have the amounts of the two classes of constituents re- 
spectively, which were consumed weekly per 100 bs. live weight of animal, 
in the case of five different series of experiments with sheep. In all cases 
the experiments extended over a period of many weeks, and in some even of 
several months. Each series comprised several pens, to each of which (except 
in Series 4, in which there were no limited foods) there was allotted a dif- 
ferent description of fixed or limited food, the ad libitum or complementary 
food being (except in Series 4) the same throughout the several pens of the 
same series, but different in the different series. In the Series 1, 2, 3 and 4, 
there were five or six sheep in each pen; in Series 5, from 40 to 50 sheep in 
each pen. 
In Series 1, the complementary or ad libitum food was Swedish turnips, 
and the limited foods were— 
In pen 1, oil-cake. 
In pen 2, oats. 
In pen 3, clover-chaff. 
In pen 4, oat-straw chaff. 

