782 EXPERIMENT STATION RECORD. 



"Neither daytime nor nighttime is shown to he superior as a milk-producing 

 period. 



" Different cows differ iu their power to make milk from food, and the same cow 

 varies in this respect from time to time. 



" It pays to select the individual according to her power to manufacture milk 

 from food, and according to the character of the product. 



"Aside fioin the influence of food or environment each animal exhibits individual 

 variations of her own, and such variations tend to show something like periodicity 

 in the separate functional activities of the animal body." 



Test of the Guernsey cow Suke of Rosendale (6520 GJ-. H. B.) 



F. W. Woll ( Wisconsin 8ta. Rpt. 1897, pp. 153-160, Jig. 1).—A test of 

 this cow for one week just after calving by one of the owners " shows a 

 total production of 189.7 lbs. of milk and 14.98 lbs. of butter fat, making 

 the average fat content of the milk produced during the week 7.90 per 

 cent." For the purpose of studying the quality of the milk during the 

 progress of lactation, samples were sent to the station on the 20th to 

 21st of each month during the winter, spring, and summer until the 

 cow was dried oif. The methods of analysis employed are described 

 and the results of this study are tabulated, together with a summary 

 of the yield and butter fat during 4 previous periods of lactation. The 

 milk at no time during the test equaled in fat content that shown in the 

 preliminary test of one week, indicating "that the high percentages of 

 fat in the milk shortly after calving were due to abnormal conditions 

 in the cow at the time."' During the 285 days of the test the cow pro- 

 duced 5,490.7 lbs. of milk with an average fat content of 5.78 per cent, 

 the total yield of fat being 317.28 lbs.,' an average of 1.11 lbs. per day. 



A new proteid constituent of milk, A. Wroblewski (Ztschr. 

 Physiol. Chem., 26 (1898), No. 3-1, pp. 308-313).— The author finds that 

 besides casein, albumin, and globulin, milk contains a fourth proteid, 

 which he calls opalisin, on account of the opalescence of its solutions. 

 The new proteid is obtained by precipitating the casein with acetic 

 acid, and then saturating the curd with either magnesium sulphate, 

 ammonium sulphate, or common salt. This precipitate differs from 

 casein by not leaving any residue of pseudonuclein on digestion with 

 pepsin. A neutral solution of the precipitate treated with a few drops 

 of calcium chlorid and considerable phosphoric acid solution gives a 

 precipitate of the opalisin. 



It is present in considerable quantity in human milk, less in mares' 

 milk, and in very small quantity in cows' milk. This constitutes 

 another difference between human milk and cows' milk. The difficulty 

 of precipitating the casein of human milk is said to be due to its opal 

 isin. Mares' milk is in this respect, as in many others, intermediate 

 between human milk and cows' milk. 



The characteristics of opalisin are described. 



On the yield and composition of sows' milk, W. A. Henry and 

 F. W. Woll ( Wisconsin Sta. Rpt. 1897, pp. 10-19, Jig. J).— Four farrow- 

 ing sows were selected, 3 being pure-bred Poland Chinas and 1 a grade 

 Chester White. Two of the sows were 2 years old and weighed nearly 



