No. 3, April, 1921] PHYSIOLOGY 305 



alcohol acts more slowly. Phenols cause the liberation of hydrocyanic acid. Aldehydes also 

 cause the liberation of hydrocyanic acid, but without plasmolj'sis in proportions of 10-20 

 drops to a liter. Trioxymethylene 0.2 gm. per liter, and 10 drops of 25 per cent formaldehyde, 

 cause the liberation of HCN. Acroleine, 1 drop per liter, causes plasmolysis, and with 50 

 drops per liter it stops fermentation. Quinone, pyridine, HCl, and H2SO4 cause plasmolysis. 

 — C. H. Farr. 



2116. Lewis, Fraxcis J., and Gwtnethe M. Tuttle. Osmotic properties of some plant 

 cells at low temperature. Ann. Bot. 34: 405-416. Fig. 1-5. 1920. — -The authors carried out 

 serial determinations of osmotic pressure, electrical conductivity, and amounts of sucrose, 

 maltose, and glucose in leaf tissues of both woody and herbaceous evergreens. They hesi- 

 tate to record any correlation between these values and the temperature records on the 

 results of the work on one season only, but they note the occurrence of maximum osmotic 

 concentration either in December or in March. They found that the osmotic pressure was 

 due chiefly to nonelectrolytes, the concentration of electrolytes changing but little throughout 

 the season. Sugars disappear progressively from winter to summer, glucose being the last to 

 be removed. An important fact in relation to resistance to frost-injury is revealed by super- 

 cooling experiments. Whereas the sap extracted from leaves of Pyrola froze at about — 3°C., 

 the leaves themselves could be cooled to — 32°C. before freezing. A significant observation 

 is also recorded regarding the chloroplast, which was seen to become disorganized during 

 the winter months, the chlorophyll distributing itself around the nucleus, coalescing to 

 form plastids again in April.— F. J. Lewis. 



2117. Shull, Charles A., and S. P. Shull. Absorption of moisture by gelatin in a sat- 

 urated atmosphere. Amer. Jour. Bot. 7:318-326. 1 fig. 1920.— The authors summarize 

 briefly the work of von Schroder on the absorption of water by gelatin from liquid water 

 and from a saturated atmosphere. On repeating a part of his experiments they obtained 

 very different results, finding that gelatin absorbed much more water from a saturated atmos- 

 phere than von Schroder reported. Instead of reaching an equilibrium at a gain of 40 per 

 cent in about a week, this absorption continued steadily until the end of the experiment 

 (47 days), when water equal to over 170 per cent of the gelatin had been absorbed. — Equations 

 for the curves of moisture intake are given. The authors call attention to the difficulty of 

 maintaining a saturated atmosphere, and suggest that the difference between their results 

 and von Schroder's is due to their greater success in this respect. — E. W . Sinnott. 



WATER RELATIONS 



2118. BiRCH-HiRSCHFELD, LuiSE. Untersuchungen iiber die Ausbreitungsgeschwindig- 

 keit geloster stoffe in der Pfianze. [Rate of transfer of dissolved substances in the plant.] 

 Jahrb. Wiss. Bot. 59: 171-262. 1919. — The author has investigated in various plants the 

 rate of conduction of solutions of lithium nitrate, ammonium carbonate, alcohol, methylene 

 blue, eosin, and other substances in the parenchyma of the cortex and in the phloem. The 

 downward movement of certain of these solutions in the water-conducting channels, simul- 

 taneous with the upward movement of the transpiration stream, was also studied. The 

 experiments were undertaken with the object of throwing new light upon the natural transfer 

 of materials in the plant. Conduction in the phloem was found to be at approximately the 

 same rate as in the parenchyma, and not in excess of the rate of transfer by simple diffusion. 

 Transpiration proved to be without influence upon the rate of transfer, in the phloem, of 

 the substances employed. Potometer measurements of the water conducted by stems from 

 which a length of the central cylinder had been removed showed the tissues outside the cam- 

 bium to be able to conduct only from loffir to ttj.Vuu of the water required by a normally trans- , 

 piring branch. Lithium nitrate in solution was found to pass, though very slowly, through 

 the thickened and cutinized endodermis of Convallaria majalis. The cuticle of the leaves 

 of a number of plants was found to be relatively highly permeable to lithium nitrate solu- 

 tion, as was shown by the detection of the salt in the leaf and stem at some distance from a 

 point on the intact upper side of a leaf where a drop of the solution had been placed. When 



