372 Royal Society of Sciences at Goitwgen. 



juice contained in the marrow furnishes to the buds their 

 first nourishment, as the cotyledons furnish it to the voung 

 plant: he is forced to add that these fibres are developed from 

 the buds, which give them birth, to the roots, with a rapi- 

 dity which hi compares to that of light or electricity, be- 

 cause the ligneous layer is formed upon the whole extent of 

 the tree in the space of a few days. The necessity of ad- 

 mitting so rapid a development is already, as has been seen, 

 a strong difficulty against this opinion. There is another 

 objenion which seems still more forcible : where we engraft 

 one kind of tree upon another, a pear-tree, for instance, 

 upon an apple-tree, each species forms its own wood in the 

 parts which come from itself; "the graft has apple-tree wood 

 only, and every thing above the insertion is pear-tree wood 

 only. We may distinctly observe the place where the two 

 woods are separated; and, as great care has been taken to 

 strip the graft of its buds, it must necessarily follow, that 

 its wood was furnished by the bark alone ; for how, the 

 partisans of the antient doctrine ask, can pear-tree buds 

 produce apple-tree wood? It is, answers M. du Pctit- 

 Thouars, because the fibres which descend from these buds 

 cannot be nourished in their passage along the'trunk of the 

 • apple-tree, except from the juices furnished to them by the 

 latter. 



[To be continued.] 

 ROYAL SOCIETY OF SCIENCES AT GOTTINGEN. 



This learned body has offered a prize of fifty ducats for 

 the best memoir Qn the following subject: — " The differ- 

 tnce of colour remarked bct\veen the arterial and venous 

 blood, has made several men of science believe that there 

 exists a similar difference in the blood of the foetus in an 

 inverse ratio: but, as experience has not confirmed this opi- 

 nion in any way with respect to new-born infants, the so- 

 ciety desires th it, by inquiries and direct experiments upon 

 children born of healthy mothers, either by the prompt ty- 

 ing up of the umbilical cord at its two extremities at the 

 moment of birth, or in any other manner, we should deter- 

 mine if there really exists an inverse difference in the co- 

 lour 



