October 8, 1870.] 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
283 
is increased by adding meal to the ordinary liay 
fodder. 
The conclusion at which Voit arrives is the follow¬ 
ing. He says, “ As regards the main question, it 
appears that, on the whole, the cow took up into the 
circulation from the fodder, 1658 grams of fat, or 
four-fifths of the fat contained in the milk; the 
562'35 grams nitrogen in the urine corresponds to 
3602 grams albumen, which, according to our views, 
yields 1851 grams fat (100 albumen = 51 fat).” 
“ Therefore, we have in all 3509 grams fat available 
from the food and the albumen. However, the milk 
contained only 2024 grams of fat, so that there re¬ 
mains over and above that 1485 grams fat, which is 
nearly sufficient for the formation of the milk sugar 
in such a manner that, in the foregoing case at least, 
there is no necessity for having recourse to the hy¬ 
drates of carbon for the wanting fifth of the fat, or 
probably for the milk sugar either.” 
This calculation is as clear as possibly can be; 
all the albumen of the fodder passing into the circu¬ 
lation is supposed to be converted, in the body of the 
cow, into casein, urea and fat; any deficiency of fat 
in the milk is made up by albumen, and whatever 
fat remains over is converted into milk sugar. 
But in regard to the validity of tills calculation, 
there are very important objections. 
It is, in the first place, a thoroughly well-established 
fact that, for keeping up a given condition, an animal 
requires a certain quantity of albuminates and noil- 
nitrogenous substances for the performance of its 
internal work; the nitrogen of the albuminates is 
eliminated in the urine and fieees, in the former as 
urea and hippuric acid, etc. 
A cow producing milk requires a larger quantity 
of fodder than a working ox, and the fodder must 
contain the same proportion of albuminates as in 
the latter case,—for 100 pounds live weight 0‘23 
pounds albuminates, and from T25 to 1'4 pounds 
lion-nitrogenous substances, according to Settegast. 
In both animals the quantity of nitrogen taken up is 
the same; in the cow, a part of the nitrogen passes 
into the milk as casein, and the remainder into the 
urine and faeces. Deducting from the nitrogen in 
the urine of the ox that quantity of nitrogen which is 
contained in the milk of the cow, the remaining nitro¬ 
gen in the urine of both animals will be the same. 
The weight of both animals remains unaltered, and 
it is clear that the albuminate which becomes casein 
in the cow is expended for work in the body of the 
ox. On the whole, the secreted quantity of nitrogen 
is the same in both cases, but the quantity in the 
urine of the ox is larger than in that of the cow. 
Consequently, if all the albumen corresponding to 
the nitrogen in the urine were, as Voit thinks, 
together with the fat from the fodder, converted into 
urea and milk in the body of the cow, much as corn 
is converted in a mill into bran and meal, there 
would not be any albumen left for the vital economy 
of the animal. This leads obviously to the assump¬ 
tion that the cow had lived solely at the cost of the 
non-nitrogenous constituents of the fodder, and had 
thereby performed its internal work. 
But, assuming on the contrary that the albumen 
corresponding to the nitrogen in the urine has served 
for internal work and for replacing material elimi¬ 
nated from the body by metamorphosis, it would then 
follow that the products of tliis metamorphosis had 
been applied for the production of milk, and that 85 
per cent, of these products consisted of urea and fat. 
Then, if we seek for the reasons by which, regard¬ 
less of all that we know as to the products of meta¬ 
morphosis in the animal body, we are to be induced 
to regard such conclusions as valid, we find them 
thus stated by Voit:—* 
“ Since I do not at present know any better, I take 
it for granted that from 100 albumen there are pro¬ 
duced 33’5 urea and 51*4 fat.” 
This is, indeed, the actual basis of Voit’s theory 
respecting the production of milk, a purely suppositi¬ 
tious breaking up of albumen into fat and urea in 
proportions that suit his calculation, adopted solely 
to serve, in the absence of facts, as the foundation 
for an imaginary explanation. Consistent with tliis 
is Voit’s procedure in dealing with ascertained facts 
concerning the production of milk, so as to make them 
agree with his views ; in his hands, such facts are 
like wax, to which the wished-for form is given by 
kneading it. 
In scientific investigation such a mode of proceed¬ 
ing does not convince any one; it is always a sign 
that facts are wanting which would speak for them¬ 
selves. 
After all the laborious work and all the multipli¬ 
city of analyses that have been made, we are not one 
step further advanced in our knowledge as to the 
origin of fat and milk-sugar in the milk of the cow; 
and, as I believe, the reason of this is, that the ques¬ 
tion has not been properly stated. Let us only sup¬ 
pose that Voit had in his experiments selected an¬ 
other cow,—one that gave little milk instead of one 
that gave much; it is highly probable that his cal¬ 
culation would then have come out still more favour¬ 
ably for his theory than was actually the case; it 
might have happened that the quantity of urea ex¬ 
creted by this cow should have been just as large as 
in the experimental case, and then by calculating 
the urea as albumen, there would have been enough 
of this substance available for the production of all 
the constituents of the smaller quantity of milk, the 
casein, the fat and the milk-sugar together, and, in 
such a case, it would not have been at all necessary 
to regard the fat of the fodder as taking part in the 
production of milk. It must be evident that as Voit 
puts the question at issue, its decision would, in 
any case, have been in favour of his preconceived 
view; the more unfavourable the conditions, the 
better would the calculation have suited. 
In the treatment of physiological problems there is 
only too often an opportunity of observing the ab¬ 
sence of that strict method which does not permit of 
data being applied for drawing conclusions before 
their sufficiency for this purpose has been fully es¬ 
tablished; thus, for instance, Voit calculates the ni¬ 
trogen in the urine of his experimental cow as albu¬ 
men, although he knows that a considerable portion 
of that nitrogen belongs not to urea, but to hippuric 
acid, which contains, relatively to nitrogen, eighteen 
times as much carbon, which then figures in the cal¬ 
culation as fat. In doing tliis, Voit relies upon 
Meissner, who thinks himself justified in concluding 
from his experiments that the non-nitrogenous pro¬ 
duct of hippuric acid must be derived from non-nitro¬ 
genous constituents of the food. However, the facts 
ascertained by Meissner are susceptible of an en¬ 
tirely different elucidation, and, in particular, we 
know that benzoic acid as well as bitter-almond oil, 
* Ojp. cit. p. 116. 
