416 On the Value of the Oil m Linseed-ccike as a Food for Stock. 
ones 15| lbs. When it is remembered the extreme and well- 
known care with which all the experiments of Lawes and 
Gilbert have been conducted, I venture to think this singular 
identity of result will be accepted as evidence of a correspond- 
ing care and exactness in the management of the Norfolk 
experiments. 
It has been already shown that the dry food required to pi'o- 
duce 100 lbs. increased live-weight was much larger when the 
cake less rich in oil was employed in the Norfolk experiments 
than it was when the more oily one was used. It appears, 
however, that in the case of the sheep fed in 1850-1, 29 lbs. 
more food were required to give the same increase as the less 
productive of the Norfolk pens. Possibly the chief explanation 
of this fact is to be found in the great improvements of the last 
half century, which have been so universally effected in almost 
every breed of sheep, a steady progress involving the capacit}', 
economically and generally, to make the best of feeding oppor- 
tunities. In the paper on the com])osition of oxen, sheep, and 
pigs (Vol. XXI. 1st Series of this Journal), ]\Iessrs. Lawes and 
Gilbert give calculations of probable quantities of dry food which 
were required to give one pound of animal increase. But I am 
informed that the results of more recent experiments than theirs 
make these gentlemen disposed to think that less food is at the 
present time required to obtain a given animal increase than 
was the case when their estimate was published. In addition to 
this it may be observed that the progress of the Norfolk experi- 
mental sheep, as gauged from time to time by the scales, was 
less rapid during the later than in the earlier weeks of the 
experiment, when the sheep were less advanced in condition. 
And as the total duration of the Rothamsted experiments 
exceeded by several weeks the Norfolk ones, it appears likely 
that this circumstance may in some measure account for the 
slightly less economical results. It is true that the Rothamsted 
experiments were carried on under cover from the weather in 
a thatched building, the back and sides of which were enclosed, 
and the sheep stood upon rafters, whilst the Norfolk experiments 
were conducted in the open. Theoretically speaking, no doubt 
the less animals are exposed to the cold the less of their carbon- 
aceous food-fuel is needed to sustain the necessary temperature 
of the body, and thus more of it should be available for conver- 
sion into bodily repair or increase, in which case the same 
amount of dry food per given live-weight of animal should pro- 
duce gi-eater gain of flesh or fat in the jirotected than in the 
exposed sheep. Animals, however, are largely creatures of 
nerves, of habit, and hereditary acquirement, and not mere 
