188 ReporT OF THE CHEMIST OF THE 
Taste VIII.— Resuuts or NicHouson’s WorK wirH Lactic AcID 













BACTERIA. 
Wirnout CatciumM CARBONATE. Witu Cancium CARBONATE. 
Soluble | Amide | Soluble Amide 
nitrogen, | nitrogen, | nitrogen, nitrogen, 
Age of expressed as | expressed as | Age of expressed as | expressed as 
milk when percentage | percentage | milk when percentage percentage 
analyzed. of total | Of total ss4 analyzed. of total of total 
nitrogen in nitrogen in nitrogen in nitrogen in 
milk. | milk. milk. milk. 
ip 8.8 g8 OES Ore a 9.6 | 4.0 
0Sa3 9.2 3.6 | Oi: 9.8 4.0 
59 days | 13.2 ee 28 days | 18.0 4.0 
59 days 12.6 o:O° 3} >..20 Gaysen 21.8 2.8 
450 days 10.2 1.4 Vee Fé days 12.6 pe. 
450 days 8.4 trace | 257 days | 12.2 trace 
nitiiabety- blogeoltast [freweitiby: | 314 days | 13.2 2.8 
RRO FIERA eG, Fae tee pe tae a eae || 314 days | 12.0 3.2 
PES DO POR RE Ee | hp Arey nor! 450d bys 9U 12.6 trace 
ee eR nt ee See ey pene | 450 days | 14.0 trace 
| | 


In some of our future work bearing more directly upon the 
chemical changes taking place during the process of cheese- 
ripening, we shall have occasion to refer to this subject again. 
RELATION OF THE UNSATURATED PARACASEIN LACTATE TO THE 
CHEDDAR PROCESS OF CHEESE-MAKING. 
As previously stated, it has been supposed that the presence of 
lactic acid was, in some way or other, responsible for, or asso- 
ciated with, some of the most important changes taking place 
in the curd during the cheese-making process, such as the ac- 
quired ability to form strings on a hot iron and the change in 
appearance and plasticity of curd; but no one has previously 
been able to show beyond question that these changes were actu- 
ally brought about by an acid, or in what way they were accom- 
plished. We purpose now to show the intimate relation existing 
between the presence of unsaturated paracasein lactate and some 
of the important changes occuring in the curd during the proc- 
ess of making cheese. 
(1) Property of curd to string on hot iron due to unsaturated 
casein lactate.-—We coagulated by rennet about 27 liters of milk, 
properly ripened for cheese-making, and carried on the process 

