Imperial Institute of France. 3€ '. 



M Febiirier, a nurseryman at Versailles, has endeavoured 

 TO collect these two kinds of sap separately : with this view 

 he made a deep cut in the trunk of a tree, and filled a hlad- 

 der to the lower aperture, so that nothing should emer but 

 the liquid coming from the parts of the tree situaied he- 

 low : he then made another incision, and placed the bladder 

 at the upper part of it so as to receive nothing but the sap 

 coming from above. 



M. Feburier regards the sap collected in the lower blad- 

 der as ascending, and the other as descending juice, and oives 

 numerous observations on the proportions of both under 

 various circumstances. Wishing afterwards to be certain 

 as to the route which each sap takes in the interior of the 

 vegetable, he plunged alternately by the two extremities 

 branches of trees into coloured tinctures. In both cases, 

 these tinctures appeared to him to follow the ligneous fi- 

 bres of the medullary canal, which made him ascribe the 

 same progress to the two saps, in which he is at variance 

 with the result of other experiments made bv M. Mustul. 



M. Feburier is also of opinion that the ascending sap 

 contributes chiefly to the development of the branches: the 

 descending sap to that of the roots ; but he thinks that the 

 cambium, or that humour which transudes horizontally 

 from the trunk, and which has been regarded as the matter 

 which gives to the tree its growth in thickness, results, as 

 vfeW as the peculiar juices, from the mixture of the two 

 saps. 



The presence of the leaves necessary for producing the 

 descending sap is also of consequence for the increase in 

 thickness; but the buds, which M. du Petit Thouars makes 

 U> play a great part in this operation, have really no share 

 in it according to M. Feburier ; for it fakes place, he in- 

 forms us, while the leaves exist, and it ceases immediately 

 when they are rcnioved, whether buds are left or not. 



So I'ar as regards the flowers and fruits, M. Feburier savs 

 he has observed that the ascending sap, when it predomi- 

 nates, tends to determine the production of the simple 

 flowers and the complete development of the germs ; that 

 the descending sap, on the contrary, where it is superabun- 

 dant, produces the multiplication of tlie fl;)wers and the 

 petals, and the enlargement of the pericarps, and con- 

 sequently of the pulpy part of the fruit : principles from 

 which it will be easy to draw many useful hints, and which 

 v.'i!l also explain several practices already adopted. 



According to M. Feburier, the soit part of the wood 

 when laid bare, but protected from the contact of the air, is 



capable 



