1919] DAIRY FARMING — DAIRYING. 679 



Experiments with heifers indicated that feeding disodlum phosphate tends to 

 raise the concentration of plasma phosphate, and that feeding with calcium 

 chlorid tends to reduce it. The latter fact is explained by the known influence 

 of calcium feeding on phosphorus excretion. 



Evidence was found that the phosphorus content of blood and plasma is likely 

 to be reduced toward the end of pregnancy, even when the phosphorus containing 

 portions of the feed were increased. It is pointed out that pregnant cows 

 could perhaps utilize more phosphorus than they get under ordinary feeding 

 methods. 



The most noteworthy accompaniment of lactation observed was a marked 

 tendency for the phosphatid of the plasma to increase during the first month 

 and to remain relatively high throughout lactation. This phenomenon was 

 largely independent of the feed, and is thought to be connected with the tendency 

 for body fat to be thrown out into the blood at the beginning of lactation. 



The concentration of calcium in the blood was found to be very constant. 

 Small increases were induced by feeding calcium chlorid. The main factor 

 influencing the calcium content is held to be the mechanism controlling acidosis. 



A very full discussion of the analytical methods adopted is given, and the 

 literature on the phosphorus compounds of blood plasma is reviewed. 



Gestation v. stage of lactation as factors causing abnormal composition of 

 cow's milk, L. S. Palmer and C. H. Eckles (Amer. Jour. Diseases Children, IS 

 (1917), No. 5, pp. 41S-419).— Data previously noted (E. S. R., 39, p. 280) on the 

 chemical composition of cows' milk and the physical constants of the butter fat 

 toward the end of lactation are tabulated with some additions, mainly further 

 data for 5 of the cows as to conditions during a 7-day period ending 45 days 

 before parturition. The figures are examined for abnormalities, particularly in 

 fat percentage, protein percentage, and Reichert-Meissl number, so as to deter- 

 mine the justification for the legal exclusion from the market of milk furnished 

 by cows due to calve in less tlian 45 days. 



" The data here presented indicate clearly that cow's milk becomes abnormal 

 in composition as soon as the lactation stimulus becomes an artificial one on 

 the part of the dairyman, and that this result bears no relation to the stage 

 of the gestation period. Many cows show these abnormalities several months 

 before the next parturition, while very heavy producing cows with periods of 

 parturition the usual interval of 12 to 13 months apart may continue to produce 

 perfectly normal milk up to the very hour of the next parturition. The latter 

 are the exception, however, rather than the rule. The great majority of dairy 

 cows in this country are relatively small producers. In these cases the high 

 protein and fat content and abnormal composition of the milk fat character- 

 istic of the end of the lactation period may become important questions in 

 connection with infant feeding long before the 45-day limit is reached." 



Some observations on the eflB.ciency of the present standard agar for the 

 estimation of bacteria in milk, H. J. Seabs and L. L. Case (Jour. Bad., S 

 (1918), No. 6, pp. 531-536). — Tests are reported to show that agar prepared 

 according to the provisional recommendations of the laboratory section of the 

 American Public Health Association' does not, of itself, provide enough nutrients 

 for the growth of many bacteria of the lactic acid type. The small quantity 

 of milk added to the medium in plating 1 cc. of a 1 : 100 dilution was found 

 to supply the deficiency, but this was not true of higher dilutions. When, how- 

 ever, the higher dilutions were made in sterile 1 : 100 milk instead of in sterile 

 water, the counts obtained were in general sufficiently consistent with the 

 results of 1 : 100 dilutions. 



' standard Methods of Bacteriological Analysis of Milk, M. P. Ravenel, et al. (Amer. 

 Jour. Pub. Health, 6 (1916), No. 12, pp. 1315-1325). 



