AGKICULTUKE AT THE AMERICAN ASSOCIATION. 521 



AGRICULTUKAL CHEMISTRY. 



A liljerul jjroportion of the papers presented before the section of 

 chemistry of the American Association and the American Chemical 

 Society, which held joint meeting-.s. were in the tleld of agricultural 

 chemistry or had a qiute direct l)earing on agricultural investigation. 



The address of the vice-president of the section of chemistry, H. A. 

 Weber, was on the subject of Incomplete Observation. In this he 

 reviewed in a general wa}' the changes in our theories on a number of 

 subjects, and gave especial attention to the investigation of the assimi- 

 lation of nitrogen by plants. Beginning with the work of Boussing- 

 ault, which for a long time was the basis of the belief that plants could 

 not assimilate nitrogen, he traced the attempt to overthrow this theory, 

 closing with the classic investigations of Hellriegel, which established 

 beyond further doubt the ability of legumes to draw nitrogen from 

 the air. From the contacting evidence of investigations on this impor- 

 tant topic during a period of more than forty years, the speaker drew 

 some deductions as to the danger of inaccurate and incomplete observa- 

 tion, and the Avay in which this may temporarily hinder the progress 

 of science. 



H. W. Wiley described the nature of the work of the Bureau of 

 Chemistry of this Department, and explained the present organization 

 of the Bureau. There are now 8 laboratories, each with a quite well- 

 detined held of work, i. e., foods, sugar, dairy products, fertilizers, 

 soil analysis, road materials, insecticides and agricultural waters, and 

 dendro-chemical studies. Some special features of the work of each 

 of these laboratories were briefly reported, and mention was made of 

 some of the more comprehensive undertakings of the Bureau, such as 

 the study of the effect of environment on the chemical composition of 

 crops, notably the sugar beet and the gluten content of wheat; the 

 comparative stud}- carried on with the experiment stations on the fer- 

 tilizer requirements of plants, and the means of determining these by 

 chemical analysis; and the investigation of the effect of food preserva- 

 tives on the metabolism and digestive functions, which is now in 

 progress. 



E. A. de Schweinitz described the work of the biochemic laboratory 

 in the Bureau of Animal Industry. He explained that biochemistry 

 has now become recognized as a quite distinct branch of chemical sci- 

 ence, a number of professorships having been established, and a jour- 

 nal for biochemistry inaugurated in Europe. In a general way the 

 biochemic laboratory studies the character and properties of toxic and 

 nontoxic substances produced by bacteria within and without the body, 

 and the relation of these substances to disease and its prevention. 

 Dr. de Schweinitz described the biochemic work on tuberculosis, 

 which has had for its aim a stud}^ of the relation of the germs from 



