BOTANY. 



193 



it becomes a simpler acid. It is not improbable tliat the entire respira- 

 tion process is not sim|)]y a complete oxidation of the carbonic acid but 

 that it is accomplished by a train of successive oxidations, which at 

 first build up the higher, tiieu simpler organic acids, finally ending with 

 carbon dioxid. 



On the respiration of leaves, L. Maquenne {Compt. Rend, 119 

 {1894), Xo. 1, p}). 100-102). — The author claims that weighing and ana- 

 lyzing the gas given off by a plant during respiration is not a proper 

 means for determining the amount of oxygen taken in and carbon 

 dioxid given off, as under (;ertain conditions ordinary oxidation ]>lays 

 a very important part. 



He affirms that there are two kinds of respiration (1) normal, wlien 

 the oxygeu taken in and the carbon dioxid eliminated aie equal, and 

 (2) respiration augmented by the oxidation of pieviously elaborated 

 material in tlie leaves resulting in a much greater evolution of carbon 

 dioxid than in the normal process. In the second ])lace, if the leaf 

 be protected from the air and no oxidation permitted, the reserve mate- 

 rial will go on accumulating, and when finally i)laced in the air the 

 amount of cabon dioxid liberated should be correspondingly aug- 

 mented. The ordinary experiments with intercellular respiration will 

 demonstrate the first hypothesis. The other was shown by placing 

 detached leaves from several plants in the receiver of a mercury air 

 pump and keeping them there for a considerable time, after which 

 air was admitted and the increased liberation of carbon dioxid noted. 

 In order to eliminate errors arising from individuality, the leaves were 

 taken in pairs from the same plant, choosing those as nearly as i)os- 

 sible of the same weight and age. The gas was drawn off by a method 

 devised by Deherain and the author, and was measured and analyzed 

 in a Schlosing eudiometer used as a volumenometer. The results of 

 his experiments are given in the following table: 



Carbon dioxid liberated by detached leaves. 



These experiments could not be conducted with more delicate leaves, 

 such as wheat, lucern, or potato, as they will not live when subjected 



