130 PHYSIOLOGY IBot. Absts., Vol. V, 



solved, but proteins are left behind. The pure solution gives no precipitate with safranin, 

 contrary to the usual result with impure preparations. A polariscopic examination of the 

 relatively pure solution shows no rotation. The solution thus obtained is 2\ times as strong 

 as Griibler's trypsin. There is removed by the purification method mentioned about 35 per 

 cent of extraneous matter. — G. M. Armstrong. 



METABOLISM (RESPIRATION) 



929. Bertrand, Gabriel. Sur le mecanisme de la conservation des fruits dans l'eau 

 froide. [The mechanism of the preservation of fruits in cold water.] Compt. Rend. Acad. Sci. 

 Paris 168: 1285-1288. 1919.— The author has previously described (Compt. Rend. 168: 1162) 

 a method for preserving fruits for comparatively long periods in cold water. Later studies 

 show that a considerable pressure is generated in sealed flasks containing fruit. It has been 

 shown by Regnard that pressure may result in the death of minute animal forms. However, 

 it has been shown that yeasts, etc., resisted greater pressures than were generated in the 

 experiments performed. Cherries were preserved for eleven months under conditions where 

 no pressure developed. It was found that the fruits absorb water and that salts, acids, sugars, 

 and enzymes diffuse outward. Acidity incompatible with the growth of most bacteria was 

 developed and numerous enzymatic changes resulted in the softening and transformation of 

 the fruit. The author considers the most important factor in preservation is the exclusion 

 of oxygen and the maintenance of a rigorous anaerobic condition such that even yeasts are 

 unable to develop. Tests with guaiacum revealed an action similar to that of laccase. From 

 the observations made, the author concludes that the chances of preserving fruit by this 

 method depend 1 . 1st, on the number and vitality of the organisms brought with the fruit; 

 and 2nd, on the development of acidity and the initiation of biochemical processes resulting 

 in the disappearance of O2. Cut fruits were found to have poor keeping qualities due to their 

 inability to resist the entrance of organisms. — V. H. Young. 



930. Brooks, Matilda M. Comparative studies on respiration. 8. The respiration of 

 Bacillus subtilis in relation to antagonism. Jour. Gen. Physiol. 2 : 5-15. 1919. — Suspensions of 

 Bacillus subtilis in 0.75 per cent dextrose were subjected to various salt solutions and the rate 

 of respiration, as indicated by the evolution of CO2, was determined. NaCl and KC1, at 

 concentrations of 0.15 M and 0.2 M respectively, increase the rate of respiration. At higher 

 concentrations the rate is decreased, CaCl 2 increases the rate of respiration at a concentration 

 of 0.05 M and decreases the rate at somewhat higher concentrations. A marked antagonism 

 was observed between NaCl and CaCl 2 and between KC1 and CaCl 2 in their effects on respi- 

 ration. Antagonism between NaCl and KC1 is slight and the antagonism curve shows two 

 maxima. — Otis F. Curtis. 



931. Gustafson, F. G. Comparative studies on respiration. 9. The effects of antago- 

 nistic salts on the respiration of Aspergillus niger. Jour. Gen. Physiol. 2: 17-24. 1919. — Low 

 concentrations of NaCl (0.125, 0.25, 0.5) and CaCl 2 (0.5 M) caused an increase in respiration 

 of Aspergillus niger in the presence of 0.05 per cent dextrose as measured by the evolution 

 of C0 2 . Stronger concentrations of these salts (2 M NaCl and 1.25 M CaCl 2 ) decreased the 

 respiration, probably through their osmotic effect in decreasing the water content of the 

 mycelium. A mixture of 19 cc. of NaCl and 1 cc. of CaCl 2 (both 0.5 M) showed an antagonism, 

 in that the respiration was normal, whereas each salt alone caused an increase. The effect 

 of a substance on growth may differ from its effect on respiration, for, in the presence of 0.05 

 per cent dextrose, 0.5 M NaCl inhibited spore germination of Aspergillus niger, while 0.5 M 

 CaCl 2 and various mixtures of the two salts did not inhibit spore germination.— Otis F. Curtis. 



932. Osterhout, W. J. V. Comparative studies on respiration. 7. Respiration and 

 antagonism. Introductory note. Jour. Gen. Physiol. 2: 1-3. 1919.— The author briefly re- 

 views the literature dealing with the effect of antagonistic salts on respiration and states that 

 he has found pronounced antagonism between NaCl and CaCl 2 in their effects on this process. 

 — Otis F. Curtis. 



