41 5 Dr. Bell on the Phyftology of Tlants. 



nomena of nature from the two following ex= 

 periments. i. Having made incifions of va- 

 rious heights into the ftem, of fcverai plantSj 

 I immerfed their roots into a decoction of log- 

 wood. The roots abforbed the coloured liquor, 

 which at length began to flow from the luperior> 

 and not from the inferior, margins of the inei- 

 fions ; nor had the liquor extended itfelf much 

 ijpwards, beyond the margin of the incifion from 

 which it was difcharged. 



2. In the feafon when the fap flows mofl: abun- 

 dantly, called the bleeding feafon, a deep cut 

 was made into the branch of a growing vine, 

 and the greatefl: quantity of fap was difcharged 

 from the upper margin of the incifion : but a 

 branch of the fame tree, cut in the fame man- 

 ner, being inverted, the fap flowed mofl copi- 

 oufly from the other margin of the incifion, 

 which of courfe was now that next the root. 

 On the other hand, many experiments may be: 

 brought to prove diredlly, that, in the bleeding 

 feafon, the fap afcends from the roots towards 

 the branches; the following however may fuffice. 

 I. Early in the fpring, when little or no fap had 

 as yet entered the plane, Dr. Hcpe made a num- 

 ber of incifions, of difix^rent altitudes, into the 

 root and flem of a birch. As the fap rofe, it 

 firfl: flowed from the fuperior margin of the 

 lowed incifion, and then, in regular fuccefilon, 

 from the upper margins of the other incifions 



till 



