210 Varietäten etc. — Physiologie. 



It is pointed out that the characters derived from the midrib 

 are of no generic value for in the living species of Cycas the midrib 

 is undoubtedly Single yet on the upper surface it usually appears 

 as a ridge, bounded on each side by a furrow. If such a pinnule 

 were fossilized an impression of the upper surface would be refer- 

 red to the genus Pseudocycas and one of the lower side to the genus 

 Cycadites. It was also shown that on drying the ridge on the lower 

 side, which in an impression would be represented by a Single 

 line, coUapses down the centre, forming a groove bounded on each 

 side by a ridge. It is suggested that the pinnules of P. insignis, P. 

 Saportae, etc. have a double or a Single midrib according as the 

 impressions were made from the Upper or the lower side of a 

 fresh or a dried leaf. Thus the presence of a double or a Single 

 midrib is of no diagnostic importance. 



It is urged that in the future the genus Pseudocycas should 

 include those forms whose cuticles have the structures described 

 by Nathorst, and that Cycadites should be retained for fronds 

 resembling the living Cycas in external appearance, but whose 

 cuticles are as yet unknown. W. B. Turrill (Kew). 



Armstrong, H. E. and H. W. Gosney. St u dies on Enzyme 

 Actio n. XXII. Lipase (I V}. The Correlation of Sy n the- 

 tic and Hydrolytic Activity. (Proc. Roy. Soc. LXXXVIIL 

 p. 178-189. London 1914.) 



The authors make a comparative study of the synthetic and 

 hydrolytic activity of Lipase in the case of fats. Using the Tanaka 

 preparation a series of parallel experiments was carried out to as- 

 certain the limits within which the two opposing changes take place 

 in presence of different proportions of the interacting substances 

 and of water. The results are summarised graphically. 



Wm. B. Brierley (Kew). 



Atkins, W. B. G., Oxidases and their Inhibitors in Plants 

 Tissues. Part IV. The Flowers of Iris. (Sei. Proc. Rov. 

 Dub. Soc. XIV. 24. p. 317—327. 1915.) 



The author repeats and extends his work on the peroxidase 

 reaction of Iris flowers, with a view to determining how far the 

 activities of oxidising enzymes are dependent upon various factors 

 such as age and illumination. 



There is no correlation in the distribution of peroxidase and 

 anthocyanin, but the former is similar for related species and varie- 

 ties, active peroxidase being absent from the Pogoniris group, 

 variable in the Apogon group, and well marked in the Zz^Ä/o;? group. 



Inhibitors, producing in Peroxydase tests a negative result, may 

 be remoyed by treatment with hydrogen Cyanide as recommended 

 by Keeble and Armstrong, or by toluene water, these agents 

 rendering protoplasm permeable and allowing apparently of the 

 diffusion of the Inhibitor. 



In many cases the quantity of active peroxidase slowly increases 

 when Iris flowers are kept in darkness and in one such case the 

 production of organic peroxide was noted. 



Wm. B. Brierley (Kew). 



