New YorK AcrictLturaL Experiment Station. 205 
photungstic acid than with tannin. This is found invariably to 
be the case. Vivian! has published some results obtained with 
nine different cheeses which illustrate this point. We give his 
figures in the table following: 
TABLE J. — COMPARISON OF PHOSPHOTUNGSTIC ACID AND TANNIN- 
Saur SOLUTION IN PRECIPITATING THE NITROGEN COMPOUNDS 
CONTAINED IN WATER-EXXTRACTS,OF CHEESE. 
PERCENTAGE OF NITROGEN IN CHEESE FoUND IN FIL- 
TRATES AFTER PRECIPITATION BY— 

0 ACOA S | a a tae 1 


Hie se Puolanteite Ma Ws phe Liahant ered Geek [Nes 
Phosphotungstic acid....... ii 1.08/1 .00/0.82 0. 63/0.67|1.69)0.95)1.10/1.22)1.02 
Tannin-salt solution........./1.54/1.26/1. 20: 65/1 .16/1.87/1 08}1.36 1£4211;27 


In connection with the above results, nothing was stated in 
regard to the history of the cheeses used in the work. We have 
been able to study the action of phosphotungstic acid and tannin- 
salt solution in connection with samples of cheese that were 
under known well-controlled conditions, enabling us to know 
Something of the general character of the proteolytic changes 
taking place. We placed 25 grams of cheese curd in each of sev- 
eral Krlenmeyer flasks, added 50 cc. of water and sterilized the 
contents by heat. We then added .5 gram of concentrated lactic 
acid, in order to convert the paracasein into unsaturated para- 
casein lactate.’ To some of the flasks thus prepared we added 
sterilized pepsin, and to others sterilized rennet-extract. For 
this purpose the enzymes were prepared as follows: We dis- 
solved 600 milligrams of Parke, Davis & Co.’s aseptic pepsin 
in 25 cc. of water, added 0.5 per ct. of formalin (containing 40 
per ct. of formaldehyde), and let the solution stand until bac- 
teriological examinations, made by Mr. H. A. Harding, showed 
the absence of living organisms. The mixture was then diluted 
to 100 cc. with water, and to each flask containing cheese we 
added 10 cc. of this sterilized pepsin solution. One thousand 
parts of the mixture in each flask thus contained one part of 
pepsin. 
14Ann. Rept. Wis. Exp. Sta., 16: 171 (1899). 
15N. Y. Agr. Exp. Sta. Bul. No. 214:67 (1902). 
