DAIRY FARMING DAIRYING. 289 



Babcock test were compared and the adaptability of the coinposite Haiiijih^ to the 

 testing of cream was investigated with results summarized as follows: 



" For all practical purposes, a pipette holding 18 cc. can be used in measuring test 

 samples of sweet cream containing between 18 and 25 per cent fat. If the cream is 

 sour or contains more than 25 per cent fat, the test samjile should be weighed. 



" Considerable variation will be found in the tests of daily deliveries during a com- 

 ix isite test ])eriod. A variation of 9 per cent or more may be expected. 



"The composite sample can be applied to the testing of cream quite as success- 

 fully as in milk testing. Fifty comparisons of composite tests with 'tests from total 

 fat' showed an avei-age difference of but 0.03 of 1 per cent. 



"Composite test periods for cream should not exceed 10 days in hot weather. At 

 other seasons of the year semimonthly periods will prove satisfactory." 



Testing skim milk by tlie Babcock test, F. W. Woll ( Country Gent., 67 {1902), 

 No. 2569, p. 357). — The limit of aci-uracy of the Babcock test for separator skim 

 milk is discussed, the author considering that tests of less than 0.05 per cent are sus- 

 picious and may be taken as j)retty conclusive evidence that the tests were not prop- 

 erly made. Tests made l)y using about 20 cc. of acid and whirling for 5 minutes in 

 turl)ine testers or 7 minutes in hand testers show generally 0.10 per cent of fat. "It 

 is a safe rule to go by, to increase readings of separator skim milk tests made by the 

 Babcock test by 0.03 per cent, if these are conducted under the most favorable con- 

 ditions for the separation of the fat, and by 0.05 per cent in other cases, when too 

 little acid was used or the whirling not continued long enough." 



The spontaneous decomposition of milk at 40-44° C. and the micro-org-an- 

 isms concerned, M. Ferguson (Inang. Diss., Gottingen, 1902, j^P- 46). — In this study, 

 c'lrried on under the direction of W. Fleischmann, 50 samples of milk from two 

 dairies (taken each month from May to November) were allowed to sour spontane- 

 ously at 40, 42, and 44° C, and then examined bacteriologically. Four forms were 

 noted — two bacteria, a bacillus, and a micrococcus. These were studied at length, 

 and the effect of their growth in milk noted. Bacterium /resembled I'xicilhrs h(ctis 

 (lerofjenes, but did not agree entirely with the description of any forms of the latter. 

 Bacillus //agreed almost entirely with the hay bacilli; and Bacterinm III showed 

 many similarities with the hay bacillus and the tyrothrix species, but did not corre- 

 spond in all respects with any of them. Micrococcus /T' showed great similarity to 

 the Micrococcus (tcidl paraUictici liquefaciens of Kozai, and is thought to l)e closely 

 related to it. 



The first three forms, I, II, and 111, were more numerous and constant. All pro- 

 duced volatile acids j)rint-ipall}' and only traces of lactic acid. The micrococcus 

 l)roduced somewhat more lactic acid, in association with volatile acids, Ijut was pres- 

 ent in smaller numbers and absent in some samples. This leads the author to sug- 

 gest tentatively that in the spontaneous souring of milk at 40 to 44°, more volatile 

 acids than lactic acid are formed as a rule. The work of others is reviewed. 



On the increased resistance of bacteria in milk pasteurized in contact with 

 the air, II. L. Russell and E. (i. Hastings {Centhl. Bad. ?/. Par., 2. Ahl., 6' (1902), 

 Xo. 15-16, pp. 462-4^J9) . — This is a rei)rint of the author's latest i)aj)er on thin sub- 

 ject in the Annual Report of the Wisconsin Station (E. S. R., 13, p. 986). 



Studies on the causes of rancidity of butter, 0. Jensen {Centhl. Bait. tc. I'ur., 

 2. Alit.,8 {1902), Xos. 1, ]>p. 11-16; 2, pp. 42-46; 3, pp. 74-80; 4, pp. 107-114; -'>, H'- 

 140-144; G, pp. 171-174; 7, pp. 211-216; 8, pp. 248-252; 9, pp. 278-281; 10, pp. 309- 

 312; 11, pp. 342-346; 12, pp. 367-369; 13, pp. 406-409) .—This is an extensive inves- 

 tigation of this subject, including a review of the important literature relating to it. 

 According to our present knowledge, the decomposition of fat is of two general kinds, 

 namely, oxidation processes and hydrolytic processes. By the oxidation process the 

 unsaturated fatty acids (i. e., in butter the oleic acid) and in part the glycerids are 

 attacked, as Duclaux and others have shown. The decrease in the iodin absorption 



