On Germination. 3°9 



duration ; for, in whatever manner the a£lion of this muf- 

 cular fibre be confidered, it cannot be moved but by phyfical 

 caufes. The queftion then will be, to difcover what are 

 thefe phyfical caufes. 



It appears very certain that the caufe of mufcular move- 

 ment is owing to the nerves, fince a part in which the 

 nerves are palfied, or confined by a ligature, has no longer 

 any movement. But how does the nerve move ? Some 

 philofophers have compared its movement to the ofcillations 

 of an extended cord which is (truck : But, I. The nerves 

 are not extended: 2. They are enveloped on all fides ; where- 

 as the cord has no points of contact but at its two extre- 

 mities. 



It appears more probable to others to confider the nerve 

 as one or more veflels conftru&ed almoft like the lymphatic 

 veflels -, that is to fay, compofed of a feries of veficles in 

 which flows a fluid called the nervous fluid. I have fup- 

 pofed that this nervous fluid is of a nature analogous to 

 that of the aura feminalis. Others have fought for the caufe 

 of irritability in electricity, and the experiments on Galva- 

 nifm feem to give fome weight to this opinion. 



[To be continued.} 



XV. On the Effects of Oxygen in accelerating Germination. 

 From the Journal de Phyfique, 1 798. 



M. 



JR.. Humboldt difcovered, in 1 793, that fimple metallic, 

 fubftances are unfavourable to the germination of plants, 

 and that metallic oxydes favour it in proportion to their 

 degree of oxydation. This difcovery induced him to fearch 

 for a fubflance with which oxygen might be fo weakly com- 

 bined as to be eafily feparated, and he made choice of oxy- 

 genated muriatic acid gas mixed with water. Crefles [lepi- 

 dium fativum) in the oxygenated muriatic acid fhewed germs 

 at the end of fix hours, and in common water at the end 

 X 3 



