DAIRY FARMING DAIRYING. 1009 



decreased slightly during the first period. At 13° the original period of no growth 

 was increased, the nundier of bacteria at the end of 50 hours being no greater than 

 that in milk at 20° after 18 hours. The rapid development of bacteria after 40 hours 

 was most frequently due to the growth of the Strei)tococcus group, rather than to the 

 lactic-acid bacteria. The development of the miscellaneous species was favored by 

 the lower temperature. The preliminary icing of milk for a period of 15 hours greatly 

 reduced the number of l)acteria, the number present at the time of curdling being 

 much less than in samples not previously iced. The preliminary icing favored the 

 development of a nundjer of miscellaneous species, but delayed the development of 

 the B. acidi lacticL 



During the second period the lactic-acid l)acteria, especially B. ackll ladici, 

 increased with marvelous rapidity, their number sometimes reaching 99 per cent of 

 the total number of bacteria. The other species decreased in both relative and 

 absolute nund)ers. The li(|uefying bacteria fre<iuently disai)peared entirely. 



Th.e presence of tubercle bacilli in market milk and butter, Pawlowsky 

 {Compt. Rend. JO. Coikj. Lilcriial. If//;/. <i Ih'iiiof/r., J'ttrix, 1900, pp. 187-189). — As 

 determined by inoculation experiments with guinea pigs tubercle bacilli were present 

 in 1 out of 51 samples of milk and in 1 out of 54 samples of butter examined. A 

 bacillus resembling tlie tubercle bacillus was also present in .'! of the samples of 

 butter. 



A new metliod of sterilizing milk, C. C. L. Budde {Nord. Mejerl Tidn., 18 

 {1903) , No. -T, pp. 0,5, GO). — Tiie method depends on the action of nascent oxygen on 

 the micro-organisms in milk at a temperature above 40° C. ; it consists in the addition 

 of a small quantity of hydrogen peroxid to the milk (0.9 gm. per liter) and heating 

 rapidly to 50°; or hydrogen peroxid maybe added to milk jjreviously heated to 

 about 50°, so that it will contain about 0.85 gm. of hydrogen peroxid to the liter; 

 in either case the subsequent heating of the milk is continued for 5 to 6 hours. An 

 excess of hydrogen peroxid may be rendered innocuous by the addition of a sterile 

 infusion of eonnnon j^east. The author has applied for a patent for the method in 

 European countries. — f. w. woll. 



Sterilization of milk by means of peroxid of hydrogen, C Barthel {Nord. 

 Mcji'vi Tidn., IS {1903), No. 11, pp. 139-141).— The author discusses the results of 

 the investigations of Heidenhain, Henrietta Chick, J. Huwart, and A. Rosam on the 

 use of hydrogen jjeroxid for tlie sterilization of milk and reports a number of 

 experiments which he conducted on this iwint, with special reference to the Budde 

 method of milk sterilization (noted above). The amount of undecomposed hydro- 

 gen })eroxid in the milk was determined in the following manner: 5 cc. of dilute 

 suli)huric acid (1:3) was added to 25 cc. of milk, and to 5 cc. of the clear fil- 

 trate 10 cc. of a 10 per cent potassium iodid solution and 5 cc. of sulphuric acid 

 (1:3) were added. The free iodin was then titrated back with a tenth normal thio- 

 sulphate solution, after having been left standing in a dark place for 4 hours and fre- 

 quently shaken. It was found that an excess of only 0.05 gm. of hydrogen peroxid 

 per liter of milk is plainly noticeable by taste. If only a trace or no undecom- 

 posed peroxid is present the milk will remain sweet for a longer or shorter time, 

 according to the temperature at which the milk is kept, but after some time, when 

 the bacteria recover from the effects of the peroxid, decomposition of the milk will 

 begin. The practicability of the Budde method is questioned by the author because 

 the amount of peroxid required for different kinds of milk can only be determined 

 by frequent exact chemical titrations, and also because the commercial 3 per cent 

 peroxid, partly on account of its impurities and partly on account of its dilution, 

 can not be used in practical work, while the chemically pure peroxid is too expen- 

 sive to be used under such conditions. 



The author finds that milk to -which minimum quantities of peroxid (e. g., 0.1 

 gm. per liter) are added after heating to from 45 to 50° C. for some minutes, will 



