Morphologie und Teratologie. — Physiologie. 497 



Frage darstellt, in dem durch sie der morphologische Werth 

 der Stachelbildung nur für die untersuchte Art festgestellt wurde. 



A. Jencic (Wien). 



Copeland, E. B., Chemical Stimulation and the Evo- 

 lution of Carbondioxid. (Botanical Gazette. 35. p. S3 

 -98. Feb. 1903. 35. p. 160—183. Mar. 1903.) 



Plants experimented with , Cardamine, Ceratophyllum, 

 Poiamogeton and Elodea; chiefly the last named. Chemical 

 agents employed, Zn SOi, Cu SO^, Hg Cl 2 , Ag (NO:;)* Ni Cb, 

 KCN, I, antipyrin and also various K and Na salts. A modi- 

 fied form of the Pettenkofer apparatus is described by the 

 author as having been used, and is stated to have been 

 accurate to one-fiftieth of a milligram. 



The most important conclusion arrived at is that metallic 

 salts cause the escape of CO2 from carbonates in the cell sap. 

 This pseudo-respiration as it is termed is often many times in 

 excess of the real respiration. Cell sap of Elodea which had 

 been expressed and then filtered, and allowed to stand a number 

 of hours, was found to evolve CO2 much more rapidly under 

 chemical Stimulation than did uninjured Elodea. From this, 

 and from the fact that metallic salts, for at least a short period 

 after their addition to Solutions containing dissolved carbonates 

 in small quantities (e. g. water from the faucet), had the power 

 of driving off CO2 from that water, the author concludes that 

 the CO2 evolution following chemical Stimulation is no reliable 

 measure of true respiratory activity in such cases. Various 

 K and Na salts are said not to cause any escape of CO2 from 

 water as mentioned above and to cause an increase in the 

 respiratory activity of the plants experimented with. It appears 

 that the K salts are more stimulating than the Na salts in 

 about the proportion of their relative toxicity. 



The paper is concluded by a consideration of CO2 evolution 

 as a phase of death and also as a post- mortem phenomenon. 



Richards (New-York). 



Langer, F., Fermente im Bienenhonig. (Vortrag an der 

 Karlsbader Naturforscher - Versammlung. Schweizerische 

 Wochenschrift für Chemie und Pharmacie. 1903. p. 17, 18.) 



Alle Süssstoffe, welche die Biene in den Wabenbau ein- 

 trägt, enthalten nach Untersuchungen von v. Planta und 

 Erlenmeyer invertirende und diastatische Fermente, welche 

 zum grössten Theile aus den Speicheldrüsen der Biene stammen. 

 Durch Untersuchung der „Aktivität" dieser Fermente ergab 

 sich: Die Aktivität der echten Honige bewegte sich in immer- 

 hin als gleich zu bezeichnenden Grenzen, gekochte Honige 

 besitzen kein aktives Ferment mehr. Ein Theil des Fermentes 

 stammt aber zweifelsohne auch aus dem Pflanzenreiche. Die 



Botan. Centralbl. Bd. LCII. 1903. 32 



