402 BOTANICAL GAZETTE [may 



an increase of respiration except when their concentration is so 

 low that they have only a stimulating action. They state that 

 when the concentration is increased to the point where anesthesia 

 occurs, the rate of respiration falls below the normal. 



It is evident that this is not the case with Laminar ia, for in no 

 instance was the respiration observed to fall below the normal 

 except after prolonged exposure to high concentrations which 

 produced death. Further investigation will be necessary to deter- 

 mine the cause of these discrepancies. 



It is evident that these experiments directly contradict the idea, 

 advocated by Verw-orn (29) and his pupils, that anesthesia is a 

 kind of asphyxia and that anesthetics act by reducing respiration. 



Summary 



When Laminaria is exposed to anesthetics (in sufficiently high 

 concentration to produce any result) the initial effect is an increase 

 of respiration. This may be followed by a decrease if the anesthetic 

 is sufficiently toxic. No decrease of respiration is observed when 

 the concentration is too low to be toxic. 



These results directly contradict the idea advocated by Verworn 

 and his pupils that anesthetics act by decreasing respiration. 



Laboratory of Plant Physiology 

 Harvard University 



LITERATURE CITED 



1. Appleman, C. O., Relation of oxidases and catalase to respiration in plants. 

 Amer. Jour. Bot. 3:223. 1916. 



2. Battelli, F., and Stern, L., Einfluss der Anasthetika auf die Oxydone. 

 Biochem. Zeitschr. 52:226. 1913. 



3. Bonnier, G., and Mangin, L., Recherches sur Taction chlorophylliene 

 separee de la respiration. Ann. Sci. Nat. \TI. 3:5. 18S6. 



4. Burker, K., Eine neue Theorie der Narkose. Miinch. Mediz. Wochen- 

 schr. 57:1443. 1910. 



5. Czapek, F., Biochemie der Pflanzen. 1913 (195 ff.). 



6. Ewart, a. J., The action of chloroform on CO2 assimilation. Ann. Botany 

 12:415. 1898. 



7. Haas, A. R., A simple and rapid method of studying respiration by the 

 detection of exceedingly minute quantities of carbon dioxide. Science N.S. 

 44:105. 1916. 



