VEGETABLE SAP. 131 



We are authorised to state the result of an expe- 

 riment which we had the pleasure of witnessing two 

 years ago, viz. : Mr. Knight, of the Exotic Nursery, 

 King's Road, Chelsea, believing that the sap, after 

 being elaborated, obeyed the law of gravitation, and 

 in subsiding caused the swellings on strangulated 

 branches, fixed ligatures on the stems of a good many 

 plants in pots, which were reversed on a stage made 

 for the purpose. 



Fig. 42. 



In this unnatural position the plants grew well : the 

 swellings, however, caused by the bands, were on the 

 same side as if the plants had stood upright, namely, 

 on that nearest the top, showing, as Mr. Knight 

 properly observed at the time, that the prominences 

 are caused by some internal movement or constitu- 

 tional power of the plant entirely independent of 

 position. 



The effect, whatever may be the immediate cause 

 K 2 



