14 Proteins of Cow’s Milk 
added to the filtrate from the coagulated globulin, and the 
precipitate, which separated after long standing, was filtered 
out and digested with water. Since the resulting gelatinous 
mass could not be washed on filter paper it was suspended in 
about 400 ce. of 90 per cent alcohol, centrifuged, washed with 
absolute alcohol, and dried over sulfuric acid. This prepara- 
tion (lactoglobulin?) weighed.0.97 gm., equal to about 0.2 gm. 
per titer of the original whole milk. 
The alcohol which had been in contact with this smaller part 
of the magnesium sulfate precipitate was evaporated and the 
residual solution shaken out with ether. The concentrated 
ethereal extract was poured into acetone, and a small precipitate 
which had the appearance of a phosphatide was obtained. 
Proteoses in Milk. 
We have devoted a great deal of time to determine definitely 
whether or not proteoses are really present in milk, for this 
question is not only of interest to the physiologist, but has im- 
portance in devising methods for future investigations of the 
non-protein nitrogenous constituents of milk, as well as for mak- 
ing preparations of our so called protein-free milk which shall 
contain less protein than the product heretofore employed. 
Since our numerous experiments have yielded no results from 
which positive conclusions can be drawn only a general account 
of their outcome need be given here. 
By proceeding according to the conventional methods, first 
removing casein by precipitation with acid, and albumin and 
globulin by boiling the acid filtrate from the casein, some protein 
has always been found in solution. Repeated attempts to ob- 
tain sufficient quantities of this protein for detailed examination 
showed that not only its properties, but also its proportion varied 
greatly in different experiments, and in many ways it differed 
distinctly from typical proteoses. Our experience has convinced 
us that the protein thus escaping coagulation is largely derived 
from some one or other of the milk proteins through the action 
of the reagents used. That it is not the result of the action of 
enzymes or of bacteria in the milk seems to be excluded by the 
fact that centrifugated milk, saturated with ammonium sulfate 
