32 CHEMICAL PHENOMENA, ETC. 



the elements of carbonic acid and water, i. e. to carbon, hydrogen, 

 and oxygen.* 



These results of the elementary analysis of seeds of different 

 kinds, before and after germination, tend, therefore, to show that the 

 chemical phenomena which take place in the earliest periods of ger- 

 mination, continue to go on even after the organic matter of the 

 seed has been changed into a proper vegetable, imperfect, undoubt- 

 edly, but still possessing the essential organs of plants, — roots, a 

 stem, and leaves. Deprived of light, the blanched vegetable may be 

 said to vegetate in a negative manner, expending, exhaling the ele- 

 mentary principles contained in the seed whence it sprung. 



The general practice of sowing seeds at some depth in the ground, 

 led to the belief, for a long time, that light was prejudicial to germi- 

 nation. Sennebier had even inferred so much from his experiments, 

 which appeared to derive confirmation from those of Ingenhousz, 

 and which were instituted for the express purpose of discovering the 

 comparative influences of sun-light and darkness on the germination 

 and growth of vegetables.! But I\I. de Saussure showed that the 

 prejudicial influence attributed to the light was connected with the 

 drying of the seed, in consequence of its exposure to a higher tem- 

 perature. M. de Saussure caused seeds to germinate at the same 

 time under two bell-glasses of equal capacity. One of these shades 

 was opaque, the other was transparent, and so placed as to re- 

 ceive the diffused light of day. The tiMuperature was the same in 

 either. The seeds sprung simultaneously under both glasses. ;J 

 Within a few days, the vegetation under the transparent shade was 

 most advanced; which is exactly what we should have expected 

 from all that has already been said of the functions of the organized 

 parts subjected to the action of light. 



We are indebted to M. de Humboldt for a number of very curious 

 observations on the property which chlorine possesses of stimulating 

 or favoring germination. This action of chlorine is so decided, that 

 it is apparent even upon old seeds which will not germinate when 

 placed under ordinary circumstances. Tlie experiments of M. de 

 Humboldt were made, in the first instance, on the common cress, 

 {Icpidium sativum.) The seeds were placed in two test tubes of 

 glass, one of which contained a weak solution of chlorine, the other 

 common water. The tubes were placed in the dark, the tempera- 

 ture beinn^ maintained at about 15" cent. (59" Fahr.) In the chio 

 rine solution, germination took place in six or seven hours ; from 

 thirty-six to thirty-eight were required before it was manifest ifi the 

 seeds in the water. In the chlorine, the radicles had attained the 

 length of .0585 Kng. inch, after the lapse of fifteen hours, while 

 they were scarcely visible at the end of twenty hours in the seeds 

 submerged in water. "^ 



* The sinnll quantity nixTatod on provpntod any rsthnatos brinjt ni-tdr of the azote 

 lost. Its iirn|K)rtion was suppnst-d not to have variml. It is ivxtri-niely prt»lt:il>U>. tiuw 

 ever, that tture was some slight (nsrns;aj:enK'nt of azote, as in the pnciding ixp«'r> 

 ment. 



t Saussure. Rorh. Chimiquco, p. 2.1. X He t^.iu< ur»\ op. cit. p. 211. 



^ Hanibnidt, Flora frihrrpt'nsis subterranen. p. l.Vi. 



