268 PHYSIOLOGY [BoT. Absts., Vol. IX, 



be accurately determined, has been used by the writer as a measure of injury or recovery. 

 It is assumed that the conductivity of the tissue of Laminaria Agardhii as found in sea water 

 is normal and that a change in conductivity may be used as a measure of injury or recovery. 

 The writer then exposed such tissues to certain solutions affecting permeability (of the same 

 conductivity as sea water) for short periods. Upon returning them to sea water there was 

 complete recovery. When exposed for longer periods recovery was only partial, indicating 

 permanent injury. The writer's conception is that recovery is not a reversal of the reactions 

 which produce injur}', but that the reactions involved are practically irreversible and that 

 injury and recovery differ only in the relative speed at which certain steps take place in a 

 series of reactions which progress chiefly in one direction. — Otis F. Curtis. 



1651. OsTERHOUT, W. J. V. A theory of injury and recovery. I. Experiments with pure 

 salts. Jour. Gen. Physiol. 3 : 145-156. 1920. — Continuing work and using methods previously 

 described (see preceding entry), the writer has experimented on the effects of solutions of 

 NaCl and CaCl2 on the conductivity of tissue of Laminaria Agai dhii. Assuming that changes 

 occur in series O — *S — ^■A — >M — >B and that the resistance of the tissue is proportional to the 

 amount of M, equations are developed which make it possible to predict, after any length 

 of exposure to solutions of NaCl or CaCU, the resistance of the tissue during the e.xposure as 

 well as the resistance during recovery. The calculated data were found to agree very closely 

 with the experimental data. — Otis F. Curtis. 



1652. OsTERHOUT, W. J. V. A theory of injury and recovery. II. Experiments with mix- 

 tures. Jour. Gen. Physiol. 3: 415-429. 1921. — Equations which serve to predict injury and 

 recovery as measured by electrical conductivity of tissues when placed in pure salts (see pre- 

 ceding entry) will also serve to predict the injury and recovery of such tissues when exposed 

 to mixtures of the two salts. — Otis F. Curtis. 



1653. OsTERHOUT, W. J. V. A theory of injury and recovery. III. Repeated exposures to 

 toxic solutions. Jour. Gen. Physiol. 3: 611-622. 1921. — The equations previously used 

 (see the preceding entries) may be used also to predict the behavior of tissues when transferred, 

 with varying sequence, from sea water to solutions of the pure salts, or mixtures, and from 

 thence to other solutions of pure salts or to sea water. It is suggested that explanations 

 similar to the one advanced (see the 2 preceding entries) may be applied to other fundamental 

 life processes. — Otis F. Curtis. 



1654. ScHOENHOLZ, P., AND K. F. Meyer. The optimum hydrogen-ion concentration 

 for the growth of B. typhosus, and B. paratyphosus A and B. Jour. Infect. Diseases 28: 384- 

 393. 1921. — B. tyhposus has a range of growth equivalent to Ph 5.0-8.6, with an optimum at 

 Ph 6.8-7.0, in salt-free veal infusion broth. Large variations in the hydrogen-ion concentra- 

 tion about the optimum zone produce only slight effects on the growth of the organisms, 

 while slight variations near the limiting concentrations produce a marked effect. B. para- 

 typhosus A and B have a range of growth similar to that of B. typhosus but exhibit a greater 

 tolerance for alkali. — Selman A. Waksman. 



1655. Smith, Theobald, and Dorothea E. Smith. Inhibitory action of paratyphoid 

 bacilli on Bacillus coli. 1. Jour. Gen. Physiol. 3: 21-33. 1920. — Gas and acid formation by 

 B. coli grown on lactose bouillon is normal when following 4-day cultures of a number of 

 more or less distinct strains of the "true hog-cholera bacilli" (including also Bacillus icteroides 

 and B. suipestifer) . Acid formation is normal but gas formation is inhibited when following 

 4-day cultures of all "true paratyphoid and enteritidis types." The inhibiting effects of the 

 latter types disappear after incubation of about 3 weeks, while the former types produce 

 inhibition after about the same time. The authors suggest that the inhibition is due to some 

 metabolic product, possibly an enzyme. The presence of large numbers of the bacteria them- 

 selves did not inhibit gas formation, while the liquid remaining after centrifuging did produce 

 inhibition. This inhibiting agent can be removed by filtering through a Berkefeld filter, by 

 heating to about 100°C., or by clearing with kaolin. — Otis F. Curtis. 



