206 INFLUBNCfc OF 0X1GEN ON GERM1NAT IOK. 



wards, others with the germen downwards, and fo that the 

 water reached precifely to the level of their height ; that is to 

 fay, that it did not entirely cover them, in order that one of 

 their extremities might be in -contact with the air. The feafon 

 was favourable to germination, it being the month of Septem- 

 ber, when the thermometer indicated 17° Reaum. or about 

 21° of the thermometer of 100 degrees. On examining them 

 twenty-four hours afterwards, I found that thofe which had 

 the germen upwards, or in contact with the air, germinated 

 remarkably well, though all the reft of the fubftance of the 

 feed was immerfed in the water ; and that the others, which 

 had been placed in the water with the germen downwards, 

 though one of their extremities was equally in contact, with 

 the air, namely, the extremity oppofite to the germen, could 

 not well germinate ; tiiey merely exhibited fome figns of ger- 

 mination ; and there was no difference to be perceived be- 

 tween thofe grains and others which I had placed on their fide, 

 not upright or perpendicular to the bottom of the plate, but 

 lying down horizontally, and confequently covered entirely 

 with water. Thus it appears that perfect germination does 

 not take place unlefs when the part which con f ains the ger- 

 men is in contact with the air, although all the reft of the feed 

 be guarded againft its immediate contact. 

 Sprouted wheat J took ieeds or grains of wheat which had already germi- 

 the developed nated in the open air, and by means of the fame wax I placed 

 plant touched them in the water, fome with the germen upwards, others 

 did not 8 when it w * tn tne g ermen downwards, in the fame veffel, and with 

 was covered. the fame precautions, namely, not fuffering the water entirely 

 to cover them ; fo that thofe which had the developed germen, 

 or the fmall plant directed upwards, were in contact with the 

 air at this point only. When I examined them again, I found 

 that thofe which had the germen downwards, and which con- 

 fequently were not in contact with the afr at this part, re- 

 mained as they were, and exhibited no other fign of further 

 germination ; whilit in the others, whofe germen was expofed 

 to the air, the germination advanced, and the fmall plant 

 increafed remarkably in growth. 

 The talk is the I afterwards wiihed to afcertain, if it were indifferent whe- 



Siren^u'hUO ther a11 P artS ° f the g ermen W€re in conta & with tne ^ r > or 



jppiy. only fome of its parts. For this purpofe, I chofe a number of 



grains of wheat which had germinated well for twenty-four 



hours 



