388 CARNEGIE INSTITUTION OF WASHINGTON. 



Deterioration of such a substance in aqueous dispersion is, then, most 

 readily conceived as involving a hydrolytic decomposition of the 

 protein with resulting liberation of amino acid, and such decomposition 

 would be checked by the introduction into the solution of any one of 

 the amino acids into which the protein material tends to be hydrolyzed. 

 That the activity of the enzyme should be preserved it is evident that the 

 decomposition of its protein constituent must be checked at a point 

 earlier than that at which enzymic activity is lost. If certain amino acids 

 split off in the course of the hydrolytic changes which result in loss of 

 activity, while others are liberated only at later stages, then the former 

 and not the latter might be expected to preserve the enzymic activity. 



Both of these hypotheses are consistent with the facts thus far de- 

 termined, and both may be correct. Both are now being subjected to 

 further experimental investigation — that turning upon the differences 

 in structure among the amino acids, by tests with other substances of 

 known structure, and that resting upon the view that the enzyme is or 

 contains a protein, subject to hydrolytic decomposition in water, by 

 further tests of the rate of deterioration at different temperatures in the 

 presence and absence of amino acids. That the favorable effect of 

 glycine is more pronounced at the higher temperatures and in the tests 

 of longer duration tends to favor the view that the enzyme is of pro- 

 tein nature and that the amino acid protects it. The same view is 

 also favored by the results of a study of the influence of antiseptics 

 upon the activity of amylases which has also been completed and pre- 

 pared for publication during the past year. 



The efficient work of those who have collaborated in these different 

 investigations, whether as research assistants or volunteers, is grate- 

 fully acknowledged. 



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

 Continuation of investigations of columbium, tantalum, and tungsten, and 

 their derivatives. (For previous reports see Year Books Nos, 16, 17.) 



Dr. Smith is making a study of the alkali tungstates, and may be 

 engaged in this work for some time to come. They are numerous and 

 baffling in their constitution as well as in their analysis. He has es- 

 tablished the definiteness of several of the salts and is occupied along 

 certain lines leading to a better understanding of their constitution. 

 In the past, empiric formulas have been used in representing them, 

 but there are strong evidences that formulas now being deduced are 

 more in harmony with the constitution and behavior of these various 

 derivatives. Much attention has been paid to what has been called 

 the water of crystallization of the bodies. It is given in large amounts, 

 astonishing to those looking at the chemical formulas of these bodies. 

 Dr. Smith's study has developed that much of what has been thought 

 to be water of crystallization is actually water of constitution. The 

 recognition of the fact has contributed largely to the re-formulation 

 of the many bodies being studied. 



