302 CARNEGIE INSTITUTION OF WASHINGTON. 



In the study of pancreatic amylase attention has been directed to the 

 problem of the exact nature of the relationship between the amylolytic 

 and the proteolytic properties of our purified preparations of maximum 

 power. This question has been investigated by means of purification 

 experiments designed to obtain a concentration of proteolytic power. 

 The method of purification previously reported has been varied in such 

 a way as to secure further fractions of the material in which both pro- 

 teolytic and amylolytic activities have been studied. The optimum 

 hydrogen-ion concentrations for the proteolytic activities of prepara- 

 tions from the pancreas and from Aspergillus oryzce have been measured 

 and compared with each other and also with the optimum hydrogen- 

 ion concentrations for their amylolytic activities. 



In continuing the comparison of the three amylases the influence of 

 the concentration of hydrogen-ion upon the activity of each was inves- 

 tigated. The experiments were so planned as to cover different con- 

 centrations of hydrogen-ion, ranging from P-f h1 -6 to 10.4. The results 

 thus obtained have established the points at which hydrolysis by the 

 enzyme is prevented by acid and by alkaU, and the concentrations of 

 hydrogen-ion at which each enzyme shows its greatest saccharogenic 

 power. These results are now being prepared for pubUcation. 



The rate of production of reducing sugar at successive stages of the 

 hydrolysis of soluble starch by each of the three amylases is being 

 studied in some detail. 



Attempts at further purification of the amylase of Aspergillus 

 oryzce are being continued. 



Smith, Edgar F., University of Pennsylvania, Philadelphia, Pennsylvania. 

 Investigations with the elements columhiuyn, tantalum, and tungsten. 



Dr. Walter Van Haagen is about completing a rather extended re- 

 search on the atomic weight of boron and the atomic weight of fluorine. 

 A report on the entire investigation may be ready about the first of 

 October. A feature of this investigation is that the ratio between 

 boron and five elements (the atomic weights of which have been well 

 established) is determined with the greatest accuracy. Originally, it 

 was intended to have Dr. Van Haagen work on columbium and tanta- 

 lum, but it was thought desirable to finish the other work in hand when 

 the grant was made by the Institution and submit the manuscript to 

 the Institution. 



