New YorK AGRICULTURAL EXPERIMENT STATION. 221 
Paranuclein results from the breaking down of casein or para- 
casein and is always found in the water-extracts of ripening 
cheese. The amounts commonly found in cheese under different 
conditions we shall discuss in a future paper. 
AMIDO COMPOUNDS. 
In the work, an account of which follows, we planned to 
isolate such diamido compounds as might be present in the 
cheese examined. Two different cheeses of the normal American 
cheddar type were used to furnish material for our work. One 
was 414 months old and had been ripened at a temperature of 
18° C., possessing a mild and pleasant flavor; the other was 15 
months old,and had been ripened at a temperature of about 20° 
C., possessing a somewhat pungent but not disagreeable flavor. 
In preparing the samples for examination, the cheese was cut 
into small pieces, the rind being excluded. We used 8 to 10 
kilograms of each cheese. After drying in air at room tempera- 
ture, the cheese was placed in large bottles, covered with 90 
per ct. alcohol and digested for several days at room tempera- 
ture, with frequent agitation. The resulting alcoholic solution, 
which was of a rich yellow color, was filtered through filter 
paper from the insoluble portion, the latter being allowed to 
drain thoroughly. The insoluble residue was then dried at 60° 
C., in order to remove all alcohol, and furnished a white, 
crumbly mass. Most of the fat had been removed by the alcohol 
and probably some small proportion of the amido-acid com- 
pounds. This white mass was next extracted with several por- 
tions of water at 55° C., and the extracts filtered through ab- 
sorbent cotton, until about 25 liters of extract were obtained. 
This water-extract was treated with tannin in excess, a copious 
precipitate of caseoses and peptones resulting, which was 
removed by filtration. The excess of tannin in the filtrate was 
removed by careful addition of lead acetate, until a drop of the 
reagent gave no further turbidity, after which the precipitate 
of lead tannate was filtered and washed with water. The excess 
of lead in this filtrate was then carefully removed by the addi- 
tion of sulphuric acid, until a drop gave no additional pre- 
cipitate, the final traces of lead being remoyed by hydrogen 
