New YorK AGRICULTURAL EXPERIMENT STATION. 347 
DATA ILLUSTRATING RESULTS OF USE OF METHOD. 
We present below some of the data obtained which will 
serve to give a general idea of the results obtained by our 
volumetric method in determining the percentage of casein in 
cow’s milk. For the most part, we have worked with the milk 
of indivdual cows which were in all stages of the lactation 
period. We have thus met with more extreme variations and 
more peculiar conditions than would usually be found in ex- 
amining herd milk. It is possible that under some unusual 
conditions which have not come under our observation, it may 
be found that the method may need some slight modifications 
in details. But so far. as our observations go, varying condi- 
tions may be met by adjusting the amount of acid used to the 
requirements of complete precipitation of casein, which be- 
comes largely a matter of experience. 
The data below represent the results obtained by three dif- 
ferent workers, one of whom possessed only such training as 
comes from determining the acidity of milk, cream, etc., and 
who had received only slight instruction in the use of this 
method. For comparison, results by the “ official” method are 
also given. 
PERCENTAGE OF CASEIN IN MILK AS DETERMINED By DIFFERENT WORKERS. 



Volumetric method. 
Official 
No. of sample. Meuiodl). saeanaieh. oe 
1 2 3 
MMAD Ayres one's Se oh ae. Sah 3.09 3.00 2.95 3.10 
Jy oh Lo Se ae eee 3.36 3.40 3.45 3.45 
tak wits aie oe ROY ole tanh 3.21 3.30 3.40 3.30 
A he Wet emis «f= « cone Rk 3.16 3.20 3.20 3.10 
TION 5 dacs ache ve ao - 38 2.95 2.90 2.90 2.80 
aks cin vw ose eins einals Hh 3.11 3.05 3.10 3.15 
opt 1s ene See 2.66 3.00 3.00 3.05 
Loo Agee eee 3.34 3.20 3.00 3.10 
ee eee eee 3.62 3.55 3.60 3.55 
0 SS Sean anne 3. 20 3.30 3.20 3.10 
Oe inde secs +s +s: 3.22 3.20 3.00 3.10 
1 Se eee 2.68 2.85 2.75 2.80 
(aS oe i ee ee 2.92 3.00 2.90 2.90 
2 DS Hae Or Sees 2.79 2.85 2.80 2.95 
15 a PO ie eee 2.84 2.85 2.80 2.70 

