370 ON THE ESTIMATION OF SUGAR OF MILK. 
ART. XCL— ON THE ESTIMATION OF SUGAR OF MILK, AND 
THE DETERMINATION OF THE RICHNESS OF MILK. 
By M. Poggiale. 
None of the processes hitherto known being capable of 
furnishing, in a rapid and accurate manner, the determi- 
nation of the richness of milk, I thought that if it were 
possible to estimate quickly one of its necessary constitu- 
ents by a process of measurement, without using the balance, 
the problem would be solved. I think 1 have obtained 
this result by determining the proportion of sugar-milk. 
Several specimens of pure milk, which I obtained for 
the purpose, were submitted to chemical analysis, and the 
following represents the mean often results : 
Water 862.8 
Butter 43 8 
Sugar of Milk . . . 52.7 
Caseine .... 38.0 
Salts ..... 2.7 
1000.0 
Thus, according to my experiments, one thousand parts 
of milk contain 52.7 parts of sugar. M. Boussingault, in 
a series of observations, found a mean of 50; a difference 
no doubt resulting from a different mode of operating. The 
quantity of sugar contained in milk is therefore consider- 
able, and is subject to but slight variation. 
The process which I propose is an application of that of 
M. Barreswill for the purpose of estimating the sugar of 
milk. This kind of sugar, in common with grape sugar, 
reduces the salts of copper, and it may be easily estimated 
by applying this reaction. The proportion of salt of copper 
decomposed will give the quantity of sugar of milk. 
Preparation of the Test. — It is prepared by adding 
bitartrate of potash to a solution of sulphate of copper, 
and dissolving the precipitate which is formed by means of 
