New YorK AGRICULTURAL EXPERIMENT STATION. 218 
We have also used the excellent Nencki apparatus, distilling 
under reduced pressure the filtrarte from the tannin-salt precipi- 
tation. In comparative trials we have obtained no lower results 
‘than when we distil under ordinary atmospheric pressure. 
11. DETERMINATION OF NITROGEN IN THE FORM OF UNSATURATED 
PARACASBIN LACTATE. 
The residue insoluble in water is treated with several portions 
of a 5 per ct. solution of sodium chloride, the process being car- 
ried out as in preparing the water extract in 83 above. The nitro- 
gen in an aliquot part of the 500 cc. of this salt-extract is deter- 
mined by the Kjeldahl method. 
II. METHODS FOR THE SEPARATION AND ESTIMATION 
OF THE NITROGEN COMPOUNDS OF MILK AND THEIR 
PROTEOLYTIC PRODUCTS. 
We will briefly describe the methods used for the separation 
and estimation of the nitrogen compounds of milk and their 
proteolytic products in the following order: 
1. Determination of total nitrogen in milk. 
2. Determination of nitrogen in the form of casein. 
3. Determination of nitrogen in the form of albumin and 
syntonin. 
4. Determination of nitrogen in the form of caseoses. 
5. Determination of nitrogen in the form of amido-acid com- 
pounds. 
6. Determination of nitrogen in the form of peptones. 
7. Determination of nitrogen in the form of ammonia. 
1. DETERMINATION OF TOTAL NITROGEN IN MILK. 
Weigh about 5 grams of milk and determine the nitrogen by 
the Kjeldahl method. / 
2. DETERMINATION OF CASEIN. 
To about 10 grams of milk add 90 cc. of water at 104° F. to 
108° F. (40° C. to 42° C.) and then 1.5 ce. of 10 per ct. acetic 
acid. Agitate and warm at the temperature given above until 
