No. 1, August, 1920] PHYSIOLOGY 129 



922. Myers, R. C, and L. C. Scott. Salivary amylase. I. A preliminary experimental 

 study of its stability in saliva. Jour. Amer. Chem. Soc. 40: 1713 ITKi. 1918. Salivary amyl- 

 ase, sterilized by being passed through a Berkefeld filter, is relatively stable for one year with 

 or without such preservatives as toluene, thymol, and chloroform; nevertheless, the preserva- 

 tives mentioned are in a measure destructive, and in the order mentioned, beginning with 

 the least destructive. — The causes which lower the stability of salivary amylase are not solely 

 organisms and preservatives. The inherent chemical weakness of the enzyme molecule must 

 be taken into account. Temperatures from 18 to 30°, light, and certain compounds in the 

 saliva increase this weakness. — C. R. Hursh. 



923. Northrup, John H. Combination of enzyme and substrate. I. A method for the 

 quantitative determination of pepsin. II. The effect of the hydrogen ion concentration. Jour. 

 Gen. Physiol. 2: 113-123. Jig. 1-3. 1919. — The method described for the determination of 

 pepsin depends on the change in conductivity of a digesting egg albumin solution. The author 

 finds that the amount of pepsin removed from the solution by the substrate does not depend 

 on the size of the particles of the substrate. The optimum H-ion concentration for the com- 

 bination of enzyme and substrate corresponds to the optimum for digestion. The author 

 suggests that the enzyme combines with the ionized protein. — J. M. Brannon. 



924. Sabatier, Paul. Ferments and catalyzers. Sci. Amer. Supplem. 88:274-275, 278- 

 279. 1919. [Translated from La Revue Scientifique (Paris).] 



925. Sallinger, Hermann. Uber die angeblichen diastatischen Eigenschaften des 

 Formaldehyds. [The alleged diastatic properties of formaldehyde.] Ber. Deutsch. Chem. Ges. 

 52B: 651-656. 1919. —The author thinks he has added proof to the view that starch is indif- 

 ferent to the action of formaldehyde as an "enzyme."— G. M. Armstrong. 



926. Shull, C. A. Physiology of dormancy. [Rev. of: (1) Crocker, William, and 

 G. T. Harrington. Catalase and oxidase content of seeds in relation to their dormancy, age, 

 vitality, and respiration. Jour. Agric. Res. 15: 137-174. 3 fig. 1918 (See Bot. Absts. 2, Entry 

 173); (2) Harrington, G. T., and William Crocker. Resistance of seeds to desiccation. 

 Jour. Agric. Res. 14: 525-532. 1918 (See Bot Absts. 1, Entry 1394).] Bot. Gaz. 68: 308-310. 

 1919. — A review of the data in these papers is introduced by the statement that this study 

 "materially increases our knowledge of the physiology of dormancy and germination of seeds, 

 throws much light on the problems of vitality and respiration, and is a general contribution 

 of much significance to seed physiology. — H. C. Conies. 



927. Waksman, Selman A. A method of testing the amylolytic action of the diastase of 

 Aspergillus oryzae. Jour. Amer. Chem. Soc. 42: 293-299. 1920. — The method used for ob- 

 taining pure starch was that developed by Sherman and associates. The author made a 2 per 

 cent starch paste. This was divided into 10 cc. portions and brought to a temperature of 

 40°C. The proper amount of enzyme was added after this temperature had been reached. 

 When the starch had all been hydrolyzed, the solution lost its opaque color and became clear. 

 In order to increase the accuracy of determining when hydrolysis was complete the dry starch 

 was allowed to absorb a 0.5 per cent solution of neutral red. This evidently aided in determin- 

 ing when the solution passed from a colloidal to a clear state. The diastase from Aspergillus 

 oryzae produces a good deal of glucose. It differs from malt and pancreatic diastase, as these 

 produce chiefly maltose and but little glucose. The author finds that the Lintner method for 

 measuring saccharogenic action of different enzymes upon starch should not be used for com- 

 parative studies of different enzymes, since the end-products arc not the same in the case of 

 the different enzymes. — J. M. Brannon. 



928. Wood, Joseph T. Note on trypsin and a new method of purifying enzymes. Jour. 

 Soc. Chem. Ind. 37: 313T-315T. 1918. — The author prepared a very pure enzyme solution 

 by soaking Swedish filter paper in the impure trypsin solution, then drying quickly in a cur- 

 rent of hot air. When such paper is soaked in water for 15 to 20 minutes, the enzyme is dis- 



BOTANICAL ABSTRACTS, VOL. V, NO. 1 



