February 28, 1908] 



SCIENCE 



331 



Bacterial Growth and Chemical Changes 

 in Milk kept at Low Temperatures: M. 

 E. Pennington, "United States Depart- 

 ment of Agriculture, Bureau of Chem- 

 istry. 



Bactei'ia in milk increased in numbers at 

 a temperature of — 0.55° C. Bacterial 

 growth at the end of a week was pro- 

 nounced. There was a steady increase in 

 the number of organisms for five or six 

 weeks and at their maximum they num- 

 bered hundreds of millions. Occasionally 

 they passed the billion mark per cubic cen- 

 timeter. This occurred in spite of the fact 

 that, though the milk was never solidly 

 frozen, after ten days to two weeks it was 

 a mass of small ice crystals. Neither odor 

 nor taste indicated the high bacterial con- 

 tent and a curd was not produced even on 

 heating, until the very end of the experi- 

 ment. 



There were present at all times during 

 these experiments acid-forming, liquefying 

 and neutral organisms. Acid formers were 

 in lower and the liquefying organisms in 

 higher proportion than is commonly found. 

 Certain species, such as B. formosus, B. 

 solitarius and B. Bavenel, were especially 

 resistant to cold and frequently were the 

 predominating species, or almost in pure 

 culture at the end of the experiment. 



Storage at this temperature ordinarily 

 cuts down the number of organisms devel- 

 oping at 37° C, the maximum number 

 being found when the plates were kept at 

 20° or 0° C. The acidity increases to such 

 an extent that sometimes 100 c.c. of N/10 

 sodium hydrate are required to neutralize 

 100 c.c. of milk, but this acidity has not 

 caused a curd. 



A chemical study of the proteid of milk 

 in cold storage showed that the casein was 

 rapidly digested, until finally more than 

 30 per cent, of it was changed to soluble 

 compounds. Caseoses, amido acid and, 

 probably, peptones increase, apparently at 



the expense of the digested casein. The 

 rapidity with which this digestion takes 

 place varies in different samples, but at 

 the expiration of two weeks it is pro- 

 nounced. 



A Demonstration of a Method {with appa- 

 ratus) of showing the Electric Charge 

 of Colloids: A. B. Macallum. Reported 

 by title. 



On the Action of Nitric Acid on Nucleic 

 Acids: Walter Jones. Reported by 

 title. 



The Improhahility of a Badiotropic Re- 

 sponse: C. Stuabt Gagee. Reported by 

 title. 



Glycocoll as a Product of Uricolysis: Ly- 

 man B. Stookey. Reported by title. 



A Study of the Influence of Potassium 

 Cyanide on the Excretion of Nitrogenous 

 Substances in the Urine of Dogs: Will- 

 iam H. Walkee. Reported by title. 

 Transmitted by Charles L. Parsons, sec- 

 retary of Section C. 



B. E. Curry, 

 Press Secretary 

 New Hampshire College 



TEE AMEBIGAN CHEMICAL SOCIETY 

 CHICAGO MEETING 



The meeting of the American Chemical 

 Society in Chicago was attended by some 

 350 chemists and was one of the most suc- 

 cessful in its history. One hundred and 

 thirty papers were presented at the meet- 

 ing, including several important addresses 

 of general interest, which required the so- 

 ciety to meet in six subsections. 



The reelection of Marston T. Bogert as 

 president was announced and of H. P. 

 Talbot, Louis Kahlenberg, A. E. Leach, 

 Wm. D. Richardson and W. Lash Miller as 

 councilors at large. 



The meeting was marked by enthusiasm 

 throughout and the announcement that the 



