1920] DAIRY FARMING DAIRYING. 579 



{Jour. Biol. Chem., J,S {1920), No. 1, pp. 2^/-23o).— Observations were made of 

 tlie acidity and the hnicocyte and streptococcus content of 124 samples of milk, 

 as a further test of the above-noted hypothesis of Van Slyke and Baker. 



" From the new data here given, and from liistological and • pliysiological 

 considerations, it api>ears that a more exact statement of the case would be 

 tJiat the infection causes the entrance of a serous exudate derived by the gland 

 cells directly from the lymph rather than from blood. This serous exudate is 

 neither exactly like blootl serum nor milk. When the infection has proceeded 

 to the place that actual rupture of tlie vessels occurs, then unchanged lymph 

 and bloftd would enter. The modilications in the secretions may be due to a 

 weakening of the secretory activity of tlie cells, or the exudate may have a 

 definite protective function against the bacterial infection, or botli conditions 

 may hold simultaneously." Desquamation of the glandular epithelium ac- 

 companies the secretory changes. 



Carbonic acid and carbonates in cow's milk, L. L. Van Slyke and J. C. 

 Bakeu {Sew York fitatc Sta. Tech. Bui. 69 {1919), pp. 9; also in Jour. Biol. 

 Chem., 40 (1919), No. 2, pp. SSr,-SPf). — The carbon dioxid content of 25 samples 

 of milk drawn fron\ separate quarters of the udder varied from 7 to 80 per cent 

 by volume, the usual determination being about 10 per cent. The Il-ion 

 concentration decreased in general with Increase in CO2. When milk was 

 pasteurized the CO2 was decreased, but the Il-ion concentration remained im- 

 changed. 



It is estimated that COj exists in milk as H2CO3 and as NaHCOa (or other 

 bicarbonate) approximately in the proportion 1:2. The CO2 tension in milk 

 seems to be the same as in other body fluids. 



In making the CO2 determinations the authors used the method of D. D. 

 Van Slyke (E. S. R., 37, p. 804). A 20 per cent solution of lactic acid was 

 used in place of sulphuric acid to separate CO2 from the carbonates. The 

 lower CO2 content of milk reported by previous workers is attributed to the 

 faulty use of the ordinary vacuum exhaustion method which, it was found, 

 failed to remove the CO. unless the milk was kept spread out in a tliin film 

 by constant agitation. 



Bacteriological methods for determining; the quality of milk, IT. — The 

 ndvantagos of a carbohydrate medium in the routine bacterial examina- 

 tion of milk, J. M. SiiKRMAN {Pcnn sylvan ia Sta. Rpt. 1916, pp. SOI-SIO, pis. 2, 

 fllis. 3).— This continuation of work noted in the previous report (K. S. R., 38, 

 p. 74) has l)(>en abstracted from another source (E. S. R., 36, p. 875). 



The determination of the keeping quality of milk, J. C Baker and L. L. 

 Van Slyke {New York State Sta. Tech. Bui. 12 {1919), pp. S).— Previously 

 noted from another source (E. S. R., 42, p. 209). 



A method for the preliminary detection of abnormal milks, J. C. Bakeb 

 and L. L. Van Slyke {New York State Sta. Tech. Bui. 71 {1919), pp. 3-14).— 

 Previously noted from another source (E. S. R., 42, p. 209). 



An epidemic of ropy milk, H. A. Hakding and M. J. Pruciia {Illinois Sta. 

 Bui. 228 {1920), pp. 111-124, fig. 1). — This bulletin, which is written in a popu- 

 lar style, consists of a discussion of the cause of ropy milk and an account of 

 the methods adopted to cope with a severe outbreak of the infection among the 

 patrons of a large milk plant. Thorough pasteurization (holding at 140° F. 

 for 30 minutes) and the prevention of reinoculation by careful sterilization of 

 cooling tanks, milk pumps, piping, bottle fillers, and bottles, put an end to com- 

 plaints from customers. " Ropy milk germs " were found In the water supply 

 of at least one farm, and on two occasions in material removed from the udders 

 and flanks of cows. 



I 



