‘New York AGRICULTURAL EXPERIMENT STATION. 249 
triturated and washed several times. The precipitate soon showed 
marked solubility in warm dilute salt solution and in hot 50 per 
et. aleohol. The washing was continued until all chlorides were 
removed. The precipitate was finally washed with alcohol and 
ether and dried at 100° C. It was free from chlorides. Its solu- 
bility was now slight in alcohol or salt solution. The ash con- 
tent was .81 per ct. We have noticed that the degree of fineness 
of the proteid after precipitation largely influences the ash con- 
tent. 
Preparation 4, by use of sulphuric acid.—The same method was 
followed as that described in preparation 38, except that we used 
sulphurie acid as the precipitant instead of hydrochloric acid. 
Triturating this preparation under different portions of water 
four or five times a day, we had to continue the operation 19 
days before the filtrate failed to show the presence of sulphuric 
acid. A little chloroform was added from time to time to pre- 
vent bacterial action. The proteid was found to be entirely free 
from sulphuric acid. The extreme difficulty met in this case in 
removing the sulphuric acid was due to the formation of calcium 
sulphate in the first precipitation and to its slow solubility in 
water. This preparation had an ash content of .56 per ct. Dur- 
ing the process of removing the sulphuric acid, the precipitate 
was readily soluble in hot 50 per ct. alcohol and in warm five 
per ct. solution of sodium chloride. After treatment with alco- 
hol, these solubilities were almost entirely lost. 
Preparation 5, made from lime-water solution of casein.—If we 
dissolve an ash-free preparation of casein in lime-water and add 
to this solution ?. hydrochloric acid until blue litmus is just 
turned red, no visible separation of proteid occurs. If we con- 
tinue to add acid, the proteid separates; and complete precipita- 
tion of the casein occurs when all the calcium in the original 
lime-water solution has been neutralized. This can be shown 
quantitatively in the following manner: Of the lime-water 
employed, 50 cc. required for neutralization 19.2 cc. of 2, hydro- 
chloric acid, using phenolphthalein as an indicator. We dis- 
solved .5 gram of ash-free casein in 50 cc. of this lime-water. On 
titration, the neutral point with phenolphthalein was reached 
when we had used 15.2 ce. of 2, hydrochloric acid. This means 
that calcium oxide, equivalent to 4 cc. of ®, hydrochloric acid, 
