BUREAU OF CHEMISTRY. 447 



containing sulphates; hydrogen peroxid, U. S. P., found to contain 

 acetanilid ; lead peroxid, labeled c. p., found to contain 5 per cent of 

 lead sulphate. 



Manufacturers have expressed not only in words, but in action, a 

 marked degree of willingness to supply the character of chemicals 

 needed for the analytical work of the Bureau. Difficulties relative to 

 procuring acetic acid complying with the sulphuric acid-bichromate 

 test have been experienced during this year, as in the past. This is 

 largely because of the fact that the awards are made to different deal- 

 ers from year to year, and each one in turn has the task of providing 

 an acid of suitable quality or enlisting some manufacturer to produce 

 a reagent of proper quality. 



The investigation relative to the quality of the various glacial phos- 

 phoric acids on the market has been completed and the results com- 

 piled. They clearly show that the various brands of this product are 

 variable mixtures of meta-phosphoric, pyro-phosphoric, and ortho- 

 phosphoric acids, together with smaller or larger quantities of sodium 

 phosphate. The latter is usually added for the purpose of causing 

 solidification and thus enabling the manufacturer to supply an article 

 of attractive appearance and which can be readily handled. It was 

 also found that solutions of glacial phosphoric acid reverted from the 

 lower hydrated acids continuously, and the rapidity of such rever- 

 sions depend on temperature, concentration, and the nature of asso- 

 ciated substances. It can therefore readily iDe seen that a mixture of 

 such variable composition is an undesirable chemical reagent. It is 

 further evident, in view of the fact that solutions of glacial phos- 

 phoric acid are never constant in composition, that such should not 

 be used in the manufacture of medicines to be employed in the com- 

 pounding of prescriptions. The reversion was proven to take place 

 not only in the commercial brands, but also in meta-phosphoric acid 

 made in the laboratory and of known purity. 



SPECIAL INVESTIGATIONS. 

 VEGETABLE PHYSIOLOGICAL CHEMISTRY. 



As in former years, the investigations in plant physiological chem- 

 istry, under the direction of J. A. Le Clerc, have been performed to a 

 large extent in collaboration with the various offices of the Bureau of 

 Plant Industry. For example — 



(a) Studies of cereals for the Office of Grain Investigation and the 

 Office of Grain Standardization, to determine their nutritive value 

 when grown under different conditions and to determine the localities 

 best aclapted for the production of the particular cereals in question. 



(&) Baking studies for the Office of Grain Investigation, in testing 

 the value of Marjdand Hours, which for a number of years had been 

 selected, crossed, and grown at College Park. This series of tests was 

 for the purpose of eliminating the least desirable varieties of wheat 

 under experimentation. 



(c) The analyses of wheat to test the effect of varying amounts 

 of shade on the protein and starch content, in collaboration with the 

 physicist of the Bureau of Plant Industry. 



(d) Acidity studies of peat for the botanist in connection with the 

 blueberry investigation. These results are of value in indicating 



