430 EXPERIMENT STATION RECORD. 



preservatives had not been used was any reaction obtained that could 

 be interpreted as indicating the presence of chemical preservatives. 

 Methods for the detection of formaldehyde, benzoic acid, salicylic acid, 

 saccharin, boric acid and borates, fluorids, and in some instances meth- 

 ods of quantitative determination, were presented in the report and 

 adopted provisionally by the association. 



DAIRY PRODUCTS. 



A report on this subject by the referee, G. E. Patrick, gave the 

 results of studies on the effects of preservatives on the determination 

 of albumin and casein in milk and of tests for renovated butter. 



The referee for next year was instructed to continue the study of the 

 effect of preservatives on the determination of the proteids of milk, and 

 to study methods for determining sugars in condensed milks and dried 

 milks or milk powders, and also methods of detecting adulteration 

 of butter with small quantities of foreign fats. 



A paper on milk analyses by calculation, b} T G. A. Olson, was also 

 presented. The author uses the following formula: P = .368T + 

 .33A — .383F, in which P = proteids, T = total solids, A = ash, and 

 F = fat. By using Richmond's or Babcock's formula for total solids 

 and assuming that all milk contains a definite amount of ash, namely 

 0.75 per cent, a complete analysis can, therefore, be computed from 

 determinations of specific gravity and fat content, sugar being obtained 

 by difference. Comparative data obtained by gravimetric analysis and 

 by calculation were reported. 



SOILS. 



The referee, C. G. Hopkins, explained why the work recommended 

 last year had not been carried out. He presented the results of a pot 

 culture experiment on the comparative value of steamed bone meal and 

 finely ground raw rock phosphate. As a general average, wheat made 

 slightly better gains with the rock phosphate than with the steamed 

 bone meal. 



A modified method for the determination of total phosphorus in 

 soils was presented in a paper b} T J. H. Pettit and A. Ystgard, and 

 comparative determinations by the method described and the alkali 

 carbonate method were reported. 



In a paper on the proper strength of acid to be used for determin- 

 ing available plant food in soils, b} T A. M. Peter and S. D. Averitt, 

 were presented the results of determinations with T V, ^V? and ^ normal 

 nitric acid, along with those obtained by the authors with \ nitric acid 

 and g^o hydrochloric acid the previous year. Preference was expressed 

 for the \ normal nitric acid. 



B. L. Hartwell and J. W. Kellogg reported determinations of the 

 phosphoric acid removed by crops, by dilute nitric acid, and by 



