On the Value of the Oil in Linseed-cahe as a Food for Stocl-. 407 
XXI. — On the Value of the Oil in Linseed-cake as a Food for 
Stock. By F. I. Cooke. 
It is very well known that owing to modern improvements in 
machinery, and an increase in the value of oil, as compared 
with the large reduction in price of linseed-cake, the latter pro- 
duct contains now a less amount of oil than was commonly 
found in it a few years ago. A diminution in the percentage 
of oil in a cake is necessarily accompanied by an increase in 
the other constituents, and arguments have recently been ad- 
vanced by German and other authorities tending to show 
that a cake low in oil may have a feeding value equal if not 
superior to one containing a larger amount of oil. On the other 
hand, many of our leading agricultural chemists have continued 
to put a much higher value per imit, for fattening purposes, 
upon oil than upon any other nutrients in a cake. Considering, 
therefore, this prevailing uncertainty, and the very large amount 
of linseed-cake used by the farmers of Great Britain, the present 
writer has long thought it a matter of the greatest importance 
to them that the question of the feeding value of oil should be 
accurately determined by practical experiment. 
This view being cordially endorsed by the Experiments 
Committee of the Norfolk Chamber of Agriculture, the writer 
was authorised to consult Sir J. B. Lawes ujDon the subject. 
In answer to the letter Sir John Lawes expressed the opinion, 
tliat if all the necessary precautions were taken, he saw no good 
reason why such an enquiry should not be carried out with a 
fair prospect of success ; and he most kindly consented to give 
the benefit of his invaluable experience and advice to that end. 
He further pointed out that the experiments conducted by him- 
self and Dr. Gilbert upon the feeding properties of barley and 
malt were quite successful, although the subject was one of 
considerably greater difficulty than the experiment which the 
Norfolk Chamber of Agriculture were willing to undertake. 
Sir John also acquiesced in the wish of the Chamber that sheep 
should be the medium for the purpose, and advised that a con- 
siderable number, not less than fifty or sixty of them, should 
be employed, extreme care to be taken in their selection, 
so that if two lots of sheep were fed upon the same food, the 
difierence, if any, in their respective increases should be reduced 
to a minimum. Sir John Lawes further suggested that the two 
cakes employed should differ very considerably in the amount 
of oil contained in them, and that if a cake sufficiently high in 
oil could not be obtained, steps should be taken to have one 
specially manufactured for the purpose. 
