OXYGEN RESPIRATION I3 



perature of the spadices then reaches 51° in an air temperature 

 of 15°.^ The heat production of Arum can be further increased 

 by wounding.- Also in the blossoms of Ceratozamia and some 

 palms a considerable amount of heat is freed. ^ Indeed it is 

 easy to demonstrate a considerable production of heat by many 

 other kinds of plants if the measurement of temperature is 

 carried out in a Dewar flask or a similar method used to prevent 

 dispersion of the heat. In this way it is possible, for example, 

 to obtain a temperature of 50° with foliage leaves.^ Similar 

 temperatures have been shown by the respiration of seeds of 

 various cereals. The heating of hay, which reaches a very 

 high point, is evoked by various bacteria which produce an 

 enormous amount of heat."" In the case of some plants respira- 

 tion is accompanied by the formation of not only heat but also 

 light. The great British physicist Boyle has already noted 

 that rotting wood does not glow in an air free medium. Phos- 

 phorescence of plants is actually a result of oxygen respiration. 

 Included among the phosphorescent plants are some fungi 

 such as certain species of Agaricus, Polyporus, Auricularia and 

 others,'' not to mention some algae and specific bacteria (Photo- 

 bacterium and others).' The phosphorescent bacteria soon 

 perish on the usual nutrient media ; the phosphorescence revives 

 in cultures on fish bouillon. Not until recently was this phos- 

 phorescence observed on artificial substrates of known com- 

 position.^ It takes place only within fixed temperature limits. 

 It is worthy of note that phosphorescent bacteria often belong 



1 Kraus, G. Abh. d. Xaturf.-Ges. Halle. Vol. i6. 1882; Ann. Jard. bot. Buitenzorg. 

 13: 217. i8g6. 



2 Sanders, C. B. Report Brit. Assoc. York. P. 739- 1906. [Experiments with the 

 so-called wound stimulus are of little value because they provide such radical changes in the 

 inter-relations of the several parts and components of the tissue affected. The increase in 

 the exposed surface and the interference with the normal conditions of permeability are but 

 two of the changed factors which could only be expected to increase the respiratory 

 processes.) 



■' Kraus, G. he. cit. 



4 Molisch, H. Bot. Zeitg. 66: 211. 1908; Zeitschr. f. Bot. 6: 303. I9i4- 



5 Literature references of Miehe, H. Die Selbsterhitzung des Heues. 1907; cf. also 

 Gorini, C. Atti d. Reale. Accad. dei Lincei, rendiconto (V) Vol. 23, pt. i, p. 984- 1914; 

 Burri, R. Landwirtschaftl. Jahrb. 33 : 23. 1919; and others. 



>; Smith, W. G. Gardeners' Chronicle 7: 83. 1877; Crie, L. Compt. rend. 93: 833. 

 1884; Kutscher, F. Z. f. physiol. Chem. 23: 109. 1897; Atkinson. Bot. Gaz. 14: I9. 

 1889; and others. 



'Beijerinck. Medd. Akad. Amsterdam. 1890. Xo. II. p. 7; Molisch, H. Leuchtende 



Pfianzen. 2nd ed. 1912. 



8 Chodat, R. et de Coulon. .\rch. sci. phys. et nat. Geneve (IV) 41 : 237. 1916. 



