286 CARNEGIE INSTITUTION OP WASHINGTON. 



described amylase preparations. The proteolytic activity was higher 

 in the first precipitate. Taken alone, this latter fact would suggest 

 that the usual amylase preparation may be a mixture of amylase and 

 protease, of which the protease is here concentrated in the first frac- 

 tion; but in this case the second fraction should show a higher concen- 

 tration of amylase than our usual amylase preparations, which was not 

 the case. 



In order to explain the experimental results on the assumption that 

 the proteolytic activity of our purified pancreatic amylase preparations 

 is due to the presence of an admixed protease, it is necessary to make 

 further assumptions to account for the fact that a fractional precipita- 

 tion which concentrated proteolytic activity in one fraction does not 

 concentrate amylolytic activity in the other. It is possible that a 

 partial separation of amylase and protease may have been accom- 

 plished, but that the amylolytic activity of the second fraction suffered 

 deterioration because of the extra manipulation. On the other hand, 

 the facts are equally consistent with the view that the amylolytic and 

 proteolytic activities may be properties of the same substance (analo- 

 gous to the finding of Osborne and Wells that a single isolated protein 

 may contain more than one antigenic radicle) ; and that in contact with 

 alcohol this substance tends to undergo a change by which its solu- 

 bility and amylase activity are diminished and its protease activity 

 increased. This would explain the fact that, among the products here 

 considered, the proteolytic activity is the highest in the fractions least 

 soluble in alcohol, and that when the usual final precipitate was further 

 fractioned it was possible to obtain a product with increased proteo- 

 lytic, but not one with increased amylolytic activity. 



It is planned to continue the investigation of these latter problems 

 in the future, but for the present to give precedence to those phases of 

 the research bearing directly upon food problems which have been 

 rendered urgent by war conditions. 



The efficient work of those who have collaborated in these investiga- 

 tions, whether as research assistants or volunteers, is gratefully ac- 

 knowledged. 



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



Investigations with the elements columbium, tantalum, and tungsten. (For 

 previous report see Year Book No. 16.) 



The work on the atomic weight of boron and the atomic weight of 

 of fluorine was finished in May and has been issued as Publication 

 No. 267 of the Carnegie Institution of Washington. At present I 

 am engaged upon a study looking to the separation of columbium 

 from tantalum. The first step was a review of all the methods sug- 

 gested for this purpose. They have not been separated quantita- 

 tively by any of the methods used in the past. Two or three new 

 lines have been tried and are promising good results. 



