810 EXPERIMENT STATION RECORD. 



A portable outfit for the determination of visible dirt in milk, F. O. ToN- 

 NEY (Amer. Jour. Pub. Health, 2 {1912), No. J,, pp. 280, 281, figs. 2).— This 

 apparatus consists of a Gooch crucible filter attached to a Chapman filter pump 

 which has a rubber collar for fitting over an ordinary faucet. The filtering 

 material consists of a very thin disk of absorbent cotton. 



Comparative investigations of the bacteriological and biochemical meth- 

 ods for judging milk, O. Schroeter {Centbl. Bakt. [etc.], 2. AM., 32 {1912), 

 No. 6-12, pp. 181-192).— Ot the 122 samples of milk utilized in this work, 89 

 samples consisted of ordinary market milk, 28 samples of a special milk in the 

 original bottles, 3 samples of milk drawn in the barn of the agricultural 

 institute of the University of Leipsic, one skim milk, and one milk purposely 

 mixed with the milk obtained from cows suffering with mastitis. The follow- 

 ing observations were made: (1) The total germ content on meat extract-, 

 whey-, Heyden-, and Ragit-agar, after 3 days at 38° C. ; (2) the number of 

 lactic-acid bacteria (according to Beijerinck) upon calcium carbonate-whey-agar 

 plates; (3) the number of coli bacteria (according to Harrison and Vanderleck) 

 in esculin bouillon; (4) the amount and character of the sediment obtained 

 in the leucocyte test (Trommsdorf) ; (5) the microscopic picture of the centri- 

 fuge residue; (6) the results obtained with the catalase test with 15 cc. of 

 milk plus 5 cc. of 1 per cent hydrogen peroxid at 20° C, with a special form of 

 apparatus, which is described; (7) the reductase test (O. Jensen); (8) the 

 milk fermentation test at 38°;* (9) the degree of acidity (Soxhlet-Henkel) ; 

 and. (10) the alcohol and boiling test. 



The catalase and reductase tests for the examination of milk, G. Geudens 

 {Handel. Vlaamach Natuur en Geneesk. Cong., 15 {1911), pp. 108-111). — 

 A description of the procedures and apparatus used for the catalase and reduc- 

 tase tests. The interpretation of the results is also considered. 



The Schardinger reaction of cow's milk, P. H. Romer {Biochem. Ztschr., 

 J,0 { 1912), No. 1-2, pp. 5-/.}).— This is a reply to Rullmann (E. S. R., 2.5. p. 785), 

 supported by experimental data to show that the initial milk almost always 

 gives a negative Schardiuger test. Commercial milk samples taken at Mar- 

 burg, Germany, were often found to yield negative results. The reaction will 

 not. therefore, indicate whether a given sample of milk has been heated or not. 



The effect of cooling milk upon the outcome of the Schardinger reaction, 

 R. BuBRi and H. Schmid {Biochem. Ztschr., 36 {1911), iNo. 5-6, pp. 376-388, 

 figs. -'/). — The formaldehyde-methylene blue reduction reaction is somewhat 

 dependent upon the temperature to which the milk was previously subjected. 

 Cooling reduces the time of reduction, which probably means an increase in 

 the enzym content. The solidification of the milk fat globules in this connection 

 is also considered. 



The behavior of sterile and boiled milk with rennet and acid, A. Kreidl 

 and E. Lenk {Biochem. Ztschr., 36 {1911), No. 5-6, pp. 3.5?'-563 ) .—Boiled, as 

 well as sterile milk, can be coagulated with rennet. Sterile vessels for holding 

 the milk, or sterile rennet, are not necessary, and in fact, sterile milk with an 

 acidity not over 22 cc. of tenth-normal acid when treated with sterile rennet 

 in a sterile vessel will not coagulate, though touching the milk so kept with 

 an unsterile finger, or the addition of a few drops of ordinary milk, will bring 

 about coagulation. The lactic-acid bacillus multiplies best in a slightly acidi- 

 fied milk (from 0.2 to 0.6 cc. of tenth-normal acid to 10 cc. of milk). The addi- 

 tion of an acid to a sterile milk contained in a sterile vessel, to the extent of 

 2 cc. tenth-normal hydrochloric acid to 10 cc. of milk, i)roduces no precipitation, 

 even after acidification at blood heat. 



The reaction of rennet on milk, M. Nierenstein and Jessie Stubbs {Jour. 

 Agr. Sci., .'i {1912), No. .'/, pp. 371-31o). — The conclusions drawn in this work 



