
New York AGRICULTURAL EXPERIMENT STATION. 525: 
An examination of the foregoing tables shows: 
1. In one case, heating for five minutes gave low results; in 
two other cases, good results. 
2. In general, the results varied little with increased length of 
time of heating. 
3. There was a slight tendency to higher results with increased 
length of heating, but such increase was more or less irregular 
and, at most, amounted to only 0.002 or 0.003 per cent. of nitrogen. 
4. It would, therefore, appear that entirely satisfactory results 
can be obtained by heating the solution containing albumen 
under the given conditions for 10 or 15 minutes, while an 
increased length of time of heating does not practically change 
the results. 
It may be stated that the precipitate formed always filters 
readily and washes easily. 
SEPARATION AND DETERMINATION OF THE NirroGEN CompouNnpbs 
oF Cows’ MILK. 
Below we give a brief summary of our method as we employ 
it in effecting the determination and separation of the three 
classes of nitrogen compounds present in the normal milk of cows. 
1. Zotal nitrogen compounds.— Determine the amount of total 
nitrogen by the Kjeldahl method and multiply by the factor 6.25. 
2. Caseen.— Weigh out about ten grams of milk, dilute ina 
beaker with about 90 cc. of water at 40°-42° C., and add at once 
1.5 cc. of a solution containing 1” per cent. of acetic acid, by 
weight. Stir with a glass rod and let stand three to five minutes 
longer. Then decant on a filter, wash two or three times with 
cold water by decantation and then transfer precipitate com- 
pletely to filter. Wash once or twice on filter. The washed 
precipitate and filter paper are then digested as in the regular 
Kjeldahl method for the determination of nitrogen, and the 
determination completed in the usual manner. To calculate the 
nitrogen into an equivalent amount of casein, multiply the amount 
of nitrogen by the factor 6.25. 
3. Albumen. — The filtrate obtained above in separating casein 
is placed in a water-bath and heated to the boiling temperature 
of water for 10 or 15 minutes. The filtered and washed pre- 
