BUKEAU OF ANIMAL INDUSTRY. 103 



BUTTER INVESTIGATIONS. 



The work on butter continues to support earlier results. Recent 

 results indicate that the amount of curd in butter has a direct rela- 

 tion to its keeping quality, not by furnishing more food to bacteria, 

 as has been supposed, but by reason of the oxidation of some con- 

 stituent of the curd. 



CHEESE INVESTIGATIONS. 



Material advance has been made in studying the conditions under 

 which bacteria grow in the Swiss type of cheese, particularly their 

 relation to the acidity of the medium. We have become able to 

 control the quality of Swiss cheese even under adverse factory con- 

 ditions. Cheese of excellent quality was made last fall in a Wisconsin 

 factory after all other factories had been obliged to close for the 

 season. A method has been developed for the colorimetric estima- 

 tion of hydrogen-ion concentration which will be of great value in 

 the study of the growth of bacteria and their relation to acidity of 

 the medium. 



Further studies have made it possible to obtain with considerable 

 certainty a proper growth of mold in Roquefort cheese, but the 

 proper method of accomplishing a correct and uniform salting has 

 not been perfected. It has been found that while there is some 

 difference in the fat of cows' milk and sheeps' milk it is not great 

 enough to make any real difference in the product. 



OTHER INVESTIGATIONS. 



Unsatisfactory conditions have prevented conclusive results re- 

 garding the efl'ect of silage on differently treated concrete, but it has 

 been made clear that a very appreciable amount of cement is dis- 

 solved by the silage juice. 



It has been shown conclusively that nitrogenous matter is carried 

 from the upper to the lower layers of the silage by seepage of the 

 juice. 



An experimental plant for sewage disposal is being constructed at 

 Grove City, which will include types of the three most approved 

 methods. These will be operated by the United States Public Health 

 Service. Similar arrangements are planned at Beltsville. 



DAIRY EXPERIMENT FARM AT BELTSVILLE, MD. 



Several lines of experiment have been carried on at the Dairy 

 Division experiment farm at Beltsville, Md., of which Mr. T. E. 

 Woodward is in charge. 



An experiment with fish meal for feeding cows indicated that this 

 feed produces more milk than cottonseed meal, but about the same 

 quantity of fat, the percentage of fat in the milk being lowered. 

 The cows will eat it, but do not like it. 



Twelve young calves were fed with cold skim milk. Warm skim 

 milk, and with cold and warm alternately. It appears that the cold 

 skim milk gives less satisfactory results than the warm or alternat- 



