

394 BOTANICAL GAZETTE [may 



distinguishable inner integument and nucellus, and a single layer of 

 endosperm in Arachis hypogaea and Prunus Amygdalus dulcis; (2) 

 a single integument and a layer of endosperm in Xanthium penn- 

 sylvanicum and Juglans regia; and (3) a portion of the integument, 

 a layer of perisperm, and a layer of endosperm in Cucurbita Pepo 

 and C. maxima. Details of the structure of these membranes, and 

 a microchemical and chemical study of their composition will be 

 given in a later paper. 



Summary 

 1. Quantitative measurements were made of the permea 



ipermeable 



expenmen 



2. The apparatus and method employed had the following 

 advantages over osmometers ordinarily employed: (1) the passage 



gm 



membrane 



be calculated; (3) 

 the concentration of the solution exerting the osmotic pressure 

 could be kept constant. 



3. The effect of temperature upon the permeability to water 

 of the seed coat of Arachis hypogaea was measured and the tern- 



1 



perature coefficients for io° rise in temperature were obtained. 

 An average coefficient was not calculated. Since the temperature 



coefficients 



with 



average coefficient is without significance. 



coefficient 



coefficient 



chemical 



are exclusively involved in the passage of water through the 



membrane 



temperature coefficients showed high 



temperatures and lower values at higher temperatures, and this 

 is in agreement with the behavior of temperature coefficients in 

 other processes. 



6. A comparison is made with the temperature coefficients 

 obtained in the permeability experiments of (1) Krabbe with 

 living membranes, (2) Rysselberghe with liviner membranes, (3) 



