December 21,1972.] THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
481 
COWS’ MILK AND THE BEST METHODS OE 
DETECTING ITS ADULTERATIONS. 
BY CHARLES EKIN', F.C.S. 
The physical properties of cows’ milk are too well 
known to need description. It is a slightly alkaline 
liquid, and has a specific gravity varying from 1020 
to 1031; according to the most recent analyses, it 
contains in a hundred parts, 
Water.8 7’55 
Fat.3-07 
Casein.4-04 
Milk Sugar.4’G3 
Ash. ’71 
100-00 
Milk has all the essential constituents of food¬ 
stuffs, viz., proteids, fats, amyloids and minerals in 
exactly the proper proportions to form a typically 
perfect food. These, measured by their carbon and 
nitrogen percentages, give G’S parts per hundred of 
the former to 0’7 of the latter. The phosphate of lime 
in milk is especially important to the process of the 
formation of bone, and this combined with the easy di¬ 
gestibility of milk, and as we have seen, b}^ its con¬ 
taining in proper proportions all the essential con¬ 
stituents of a perfect food, explains why it should 
and does form the diet, par excellence, for the infant 
stages of life. It would seem a work of supereroga¬ 
tion in these days of advanced knowledge to point 
this out; and, in de id nature has been teaching the 
lesson from time immemorial; but I have frequently 
heard mothers boast that their children have been 
brought up entirely without milk, whether human 
milk which is better, or its substitute from the cow, 
and that my experience cannot be altogether singular 
is sufficiently proved by the number of so-called in¬ 
fants’ foods which we see everywhere advertised. 
Although for adults the mixing of foods which 
long experience has justified is no doubt the best, 
still it is quite possible under certain conditions to 
live on a milk diet alone ; and we have here at all 
events one instance where theory and practice are 
perfectly in accord. I have been assured by one 
whose authority is undoubted, and who has lived 
several years amongst certain tribes of Arabs re¬ 
markable for their fine physique and great strength, 
that they have but one meal a day, and that that 
meal consists entirely of camels’ milk. The meal, it 
is true, must be rather a tedious affair, for owing to 
the stomach not being able to accommodate a suf¬ 
ficient quantity of the fluid at one time, they have to 
wait whilst they slowly pass the bowl from one to 
the other, until the casein has been coagulated in 
the stomach, and there is literally room for another 
draught. I am not informed •whether this process 
is facilitated, as is reported of children at school 
feasts, by “ standing up.” 
The white and almost opaque appearance of milk 
is an optical illusion; examined by the microscope 
it will be seen to be a perfectly transparent fluid, in 
which float numbers of transparent globules of fat. 
These globules are surrounded by an albuminous 
envelope, and the mechanical breaking of this, as in 
churning, causes the fat to agglomerate and become 
what is known to us as butter. 
In the process of churning, a portion of the cheesy 
matter or casein of the milk becomes mixed with the 
butter, but this can be removed to a great extent by 
Third Series, No. 130. 
repeated washings in water, and decanting off the 
particles of casein which are suspended in it. 
In the best kinds of butter the cheesy matter rarely 
amounts to more than one per cent.; in the inferior 
kinds there is often several per cent, present. As a 
rule, the more the casein is left in the butter, owing 
to its liability to putrefactive changes, the more likely 
the butter is to become rancid. 
We have been treated of late years to several 
sensational articles in the newspapers as to the 
adulteration of butter, but they have no foundation 
in fact. The adulterants are almost invariably 
water and common salt. Good honest butter, if 
fresh, contains 82 or 83 per cent, of fat, about 1 per 
cent, of salt., and 10 per cent, of water; if salted, it 
should never contain more than 7 per cent, of salt. 
It is sometimes adulterated with as much as 35 per 
cent, of water. The fat should be estimated by 
washing with ether and evaporating down the ethereal 
solution. Where much water is present a rough 
estimate may be formed by melting the butter at a 
gentle heat in a graduated tube, and measuring off 
the proportion of water, which will of course sink 
to the bottom, 
Cheese is made by coagulating the casein of milk ; 
in this country by means of rennet, in other countries 
by such diverse substances as hydrochloric acid, 
vinegar, tartaric acid, sour milk, the juice of figs or 
thistles, etc. etc.; but though the manufacture of 
cheese offers many points of interest to the chemist,, 
a discussion of them here would be foreign to the 
purpose of this article. 
The cow stands first amongst all animals as a 
milk giver, both on account of the quantity and 
quality she yields. 
The quality of the milk is much influenced by the 
age, the breed, the food, and the general conditions 
under which the animal is kept; and it becomes a 
point of importance to the analyst to know the. ex¬ 
treme limits of this variation. 
It used to be the custom to speak as to the purity 
and goodness of milk from the size and number of 
the fat globules as revealed by the microscope, but 
it is needless to say such a test is very unreliable,, 
as is also the test of specific gravity. With regard 
to this latter test, it is evident that the removal of 
all or part of the cream, which is lighter than water,, 
would increase the specific gravity, and a milk thus, 
treated would actually in this way be pronounced 
better than it was before it was deprived of its; 
cream. 
Within the last two years, thanks to Mr. Wank- 
lyn, who during that time has made several hundred- 
analyses of milk, the results of which analyses he¬ 
lms published from time to time in the ‘ Milk 
Journal ’ and elsewhere, the assa} r of milk has been 
put upon an altogether more satisfactory footing 
than it has ever been before. Mr. Wanklyn lias 
•based his conclusions upon the amount of total 
solids milk contains ; and although this method is 
not of his originating, it has been brought in liis 
hands to a completeness and degree of accuracy 
which leaves little to be desired. 
In examining a mills; accordingto his plan, small thin 
platinum dishes containing carefully weighed quan¬ 
tities of milk are to be maintained at a temperature 
of 212° F. by means of a water bath for three hours. 
The residue once dried is not found to be very hy¬ 
groscopic. This, of course, gives the total solids. 
| If it is desirable to estimate the ash as well, the 
