96 LIGHT. 



proceeding from the flowers of various plants, but whe- 

 ther they might not be resolved into electrical pheno- 

 mena connected with the atmosphere, is doubtful. 



94. Zavadski states that the light was seen only in 

 the months of July and August, whilst fructification 

 went on, and then only when the day had been warm 

 and fine, and that it appeared soonfafter sunset ; also that 

 the flashes sometimes came one after the other quickly, 

 but often after the lapse of several minutes. 



95. It has been seen at night when the weather was 

 stormy and tempestuous, and also when during the day 

 the temperature had been 88 Fah. 



96. Though, as we have stated, it may be doubtful 

 what is due to electrical conditions of the atmosphere, 

 we must mention that when the Arum maculatum was 

 allowed to respire in oxygen, greater heat was deve- 

 loped, and a phosphorescence was seen ; that the evo- 

 lution of warmth has been generally noticed in plants 

 of strong odour, and which, in some instances, has been 

 the case as regards the development of light, that both 

 heat and light have been chiefly seen when the tempe- 

 rature has been high, and that both occur, according to 

 some, when fertilisation is going on, and that therefore 

 these may be coincidences which may incline us to the 

 opinion that the combination of oxygen with carbon is 

 closely connected with the production of this pheno- 

 menon. 



97. An appearance of a luminous nature has been 

 noticed in the juices of some plants, but the condition of 

 this work forbids our entering any further upon the sub- 

 ject ; and we, therefore, must refer the student more es- 

 pecially to Meyen, where he will find the evolution of 

 light as taking place during the decomposition of vege- 

 table organic matter noticed in detail. 



SECRETION. 



98. From the introduction of nutritive material into 

 the system of a plant, and the due performance of the 



