INFLUENCE OF OXIGEN ON GERMINATION. 20-5 



' him other philofophers, have {hewn that germination does not 

 take place in any, mephitic air; as, for example, inflammable 

 or hidrogen air, phlogiftic or azotic air, which are known to 

 contain no oxigen ; whence it was neceflarily concluded, by 

 a legitimate inference, that of all the atmofphere which we 

 term the air, the oxigen is the only portion neceflary to ger- 

 mination. This has been confirmed in a more direct manner 

 by Ingenhoufz, who difcovered, that the greater the abundance 

 of oxigen the greater is the rapidity and facility of germination 

 in grains or feeds ; which probably led Humboldt to the dif- 

 co-very of the means of accelerating germination, and effect- 

 ing it even in the mod obftinate feeds, by the oxiginated mu- 

 riatic acid, or even, as Decandolle pretends, of the nitric acid, 

 which are known to be charged with oxigen. 



At prefent it remains to be afcertained what influence oxi- Oxigen >s 

 gen exerts upon growing feeds ; that is to fay, what precifely ^ce^chanfrra 

 are its effects upon germination. In order that germination the amylaceous 

 may take place, it is neceflary that there fhould be a principle P art °* feeds * 

 of fermentation in the farinaceous fubftance which refides in 

 the cotyledons or placentas of the feeds, which fubftance, as 

 every one knows, envelopes and furrounds the germen or 

 embryo; hence there is reafon to believe that this fubftance, 

 combining with oxigen by means of fermentation, acquires a 

 degree of acidity, and confequently a ftimulus proper for ex- 

 citing the vitality of the germen, and for giving the firft im- 

 pulfe to the circulation of the fluids in the embryo ; or that, 

 by means of the oxigen, this fubftance becomes modified fo 

 as to acquire particular properties, by which it is rendered 

 capable of affording the firft nourishment to the tender foetus ~ 



or embryo of the plants ; fince it has been demonftrated, by the 

 late experiments of Dr. Rollo, that in the germination of the 

 farinaceous feeds, the amylaceous part is converted, by means 

 of the concurrence and combination of the oxigen, into fac- 

 charine fubftance, or even both. 



It is not certain, however, that oxigen influences this only ; Experiments, 

 that is to fay, that thefe are its fole effects : in order therefore 

 to afcertain this point, I made the following experiments. 



I placed feeds or grains of wheat, triticum, in a plate with The feeds of 

 water, in the following manner: I fixed them to the bottom wh eat germinate 



/- \ r mo fp ee( h'y 



or the plate with loft wax, fo as to make them remain in a when the germ 

 perpendicular or ftraight direction, tome with the germen up- ,s . ; £ conta,a 



wards, 



