Descendenz und Hybriden. — Physiologie. 4S5 



PoiNDEXTER, C. C, The Development of the Spikelet 

 and Grain of Com. (The Ohio Naturalist. Vol. IV. 1903. 

 p. 3—9. Plates 1—2.) 



This study is preliminary to an investigation of xenia in 

 com. The material was common white field com. The deve- 

 lopment of the ovule and the comparative rate of growth of 

 nucellus and endosperm are considered. In later stages the 

 endosperm almost entirely replaces the nucellar tissue. 



Charles J. Chamberlain (Chicago). 



DixON, H. N., A Transpiration Model. (Sei. Proc. Roy. 

 Dublin Soc. Vol. X. [N. S.| No. 9. Part. I. p. 114-121. 

 1903.) 



The model was construeted as described below. A semi- 

 permeable membrane was fastened on the top of a thistle- 

 funnel. On this some sugar was placed and a second semi- 

 permeable membrane spread loosely over this and fastened 

 securely at the edges. The funnel was then filled with water 

 and set upright and water supplied to its lower extremity. 



The cell enclosed by the semipermeable membranes be- 

 came turgid and water was drawn up through the supply tube. 



A small amount of sugar was found to escape with the 

 water through both upper and lower membranes by leakage. 

 By evaporation the Solution passing through the upper mem- 

 brane became concentrated, and drew more water to the 

 surface. 



This modei shows that a state of tension may exist in 

 the water of leaf-cells while simultaneously the dissolved substance 

 may be exerting osmotic pressure as is proved by the fact that 

 such cells are in a state of turgidity. The tension set up by 

 evaporation at the surface of the leaf during transpiration is 

 transmitted through the solvent in these cells to the water in 

 the condueting vessels and tracheids of the leaf. 



The simultaneous action of pressure and tension in the cells 

 coupled with slight leakage of the solute through the mem- 

 branes is adequate to aecount for the observed facts of transpiration 

 into a saturated atmosphere as may be shown by enclosing 

 the cell of the model in a vessel containing water. 



E. Drabble (London). 



Marchlewski, M. L., On phylloerythrine, a new deri- 

 vative of Chlorophyll [sur la phylloerythrine]. 

 (Sitz.-Ber. d. k. Acad. d. Wiss. in Krakau, math.-naturw. 

 Classe, vom 12. October 1903.) 



Auf der Suche nach Reductionsproducten des Chlorophylls 

 in den Faeces von mit frischen Gras gefütterten Kühen, fand 

 Verf. einen neuen Körper, das Phylloerythrin, der, trotz einiger 

 äusserer Aehnlichkeit mit Schunck's Scatocyanin, sich von 

 diesem als gänzlich verschieden erwies und sich aus dem 



