DAIRY FARMING DAIRYING. 607 



the operation. Both cows rec^overed tlieir normal condition and fiow of milk within 

 a few days. 



"The results of a study extending over a period of 214 days of record with 14 dif- 

 ferent cows indicate that there is no intimate relation between the temperature of 

 the cow and either the percentage of fat or the total yield of fat. There appears to 

 he no difference in this respect whether the temperature he taken only at milking 

 time or at more frequent intervals. 



"In 214 days of record the lower percentage of fat for each day occurred 62 times 

 with the smaller yield of milk and 149 times with the larger yield of milk; 50 times 

 at the evening milking and 164 times at the morning milking; and 108 times with 

 the smaller yield of fat and 106 times with the larger yield of fat. 



"In 214 days of record with 14 different cows and comparing the morning's with 

 the night's milking on each day, 51.6 per ceiat of the total butter fat produced was 

 secreted at the milkings containing the higher percentage of fat, and 48.4 per cent 

 of the total butter fat was secreted at the milkings containing the lower i)ercentage 

 of fat." 



An extentled ljibliogra2:)hy is apj^ended. 



A study of some of the salts formed by casein and paracasein -with acids: 

 Their relations to American Cheddar cheese, L. L. Van Slyke and E. B. Hart 

 {Xi'w Turk State Sta. Bui. 214-, pp. 5S-79). — Introductory notes are given on the 

 chemical changes taking place in cheese during the early stages of its manufacture, 

 and experiments are reported the results of which are summarized by the authors 

 as follows: 



"(1) The objectof the work described in this l)ulletin isto study the real function 

 of acids in relation to the imiiortant changes taking place in cheese-curd during the 

 Cheddar process of cheese-making. 



"(2) In examining cheese for hetero-caseose \>y extraction with dilute solution of 

 common salt, a body was found in quantities so large as to indicate that it was some 

 compound other than hetero-caseose. 



"(3) In studying cheeses made with and without the use of lactic acid, the salt- 

 soluble product was discovered to be present in very large quantities only when acid 

 was used, being practically absent, or present in very small proportions, when no 

 acid was used. 



"(4) In normal cheese the salt-soluble ])roduct is always found, but in varying 

 quantities, being largest usually in new cheese, and diminishing with age of cheese. 

 Various conditions affect the amount in new cheese, especially those conditions 

 influencing the amount of acid j)resent. 



"(5) Paracasein, carefully prepared and treated with dilute lactic acid, furnishes 

 a ])roduct resembling, in both physical and chemical properties, the salt-soluble 

 substance extracted from cheese. 



"(6) Paracasein is shown to combine with an acid in at least two different pro- 

 portions, forming two distinct compounds; one is the unsaturated or mono-acid salt; 

 the other, the saturated or di-acid salt. Such compounds were prepared with lactic, 

 acetic, hydrochloric, and sulphuric acids. 



" (7) Casein forms salts with acids in the same manner as paracasein. 



"(8) The unsaturated salts formed by casein and paracasein with acids are soluble 

 in dilute solutions of sodium chlorid and in 50 per cent hot alcohol, but insoluble in 

 water. The saturated salts are practically insoluble in water, dilute salt-solutions 

 and 50 per cent hot alcohol. Both forins are sparingly soluble in dilute solutions of 

 calcium lactate and calcium carbonate. 



"(9) The important changes taking place in cheese-curd during the process of 

 Cheddar cheese-making, such as the acquired ability to form strings on hot iron, the 

 changes in appearance, plasticity and texture, and probably the shrinkage, are due 

 to the formation of the unsaturated paracasein lactate. 



