Lecture on Milk. 
415 
then, that the additional food had a tendency to go into meat or 
to produce fat. This shows that we cannot increase or improve ad 
infinitum the quantity or quality of milk. Cows which have a ten- 
dency to fixttcn when supplied mth additional food rich in oil and in 
flesh-forming materials, like linseed-cake, have the power of converting 
that food into fat ; but they do not produce a richer milk, and they 
may even produce it in smaller quantity. It is this which renders all 
investigations on the influence of food upon the quantity and quality 
of milk so extremely difficult. According to theory it would appear 
that food rich in oily or fatty matter would be extremely useful for 
producing rich milk ; biit in practice we sometimes find that it pro- 
duces fat and flesh instead. Sometimes its influence is even injmious ; 
for cows supplied too abundantly with linseed-cake produce milk which 
does not make good butter. 
A very cm-ious case of this kind was brought imder my notice some 
time ago by Mr. Bai"thi"opp. He had milk which fm-nished cream that 
could not be made into butter. When put into the chm-n it beat up 
into froth ; the casein would not separate from the butter, even in the 
cold weather of January. Mr. Barthi'opp had given his cows linseed-cake 
in considerable quantities ; and this cake, perhaps for want of being 
mixed with a sufficient quantity of good di-y hay, evidently had the 
effect of producing too much liquid fat. On trying to separate as much 
as possible the solid or crystallised fat fi'om the liquid fat, I found 
that the latter was very much in excess of the former. This is the 
most striking instance of the influence of a great excess of oily food 
on the quality of cream, and consequently on the butter, which has 
come under my notice. 
In speaking of the quality of cream, I would take this opportunity 
of remarking, that bad oilcake, and particularly bad linseed-cake, does 
a gi'eat deal more harm than is generally supposed by dairymen. The 
inferior taste of the milk is well known. ' The wholesomeness of the 
milk of stall-fed cows is fiu'ther aifected by the abominable matters 
which are occasionally put into linseed-cake. Oilcake-crushers seem 
now to have the privilege of incorporating any kind of oily refuse with 
linseed-cake ; and since this has been the case, we have heard more fre- 
quently of diseased milk, and of milk which has a disagreeable flavour. 
If cows must have extra food, and linseed-cake be preferred for the 
pm-pose, the very best and piu-est kind of cake will answer best. 
Distillery wash, the acid water of starchmakers, and similar 
refuse, make milk, as is well known, watery ; and this dispenses 
with the necessity of mixing it afterwards with water. Water is not 
so much added to milk as it is incorporated in the animal system 
before the milk is produced. It is well known that acid water, and 
especially water that contains lactic acid, has a tendency to produce 
an abundance of milk. When animals are fed with concentrated food, 
such as bean-meal or cake, it may, perhaps, be advisable — in the 
absence of brewers' grains or distillery refuse, — two materials which 
contain lactic acid — to generate some lactic acid by keeping barley- 
meal for some time in contact with water, and by letting it slightly 
ferment, some vegetable matter perhaps being added, which has a 
