106 EXPERIMENTS AND OBSERVATIONS ON THE 



of the bark possessed the powers I attributed to them, I concluded that 

 the sap would be impelled to the inverted ends of the layers, and be 

 there employed in the production of new wood and roots ; and in this 

 my expectations were not disappointed. At the proper end of the layers, 

 the wood immediately beyond the buds became dry and lifeless early in 

 the succeeding summer ; the stems also, between the buds and the 

 mould in the pots, increased in size as usual ; and nothing peculiar 

 occurred. But at the inverted end appearances were extremely dif- 

 ferent : new wood here accumulated rapidly beyond the buds, and 

 numerous roots, of considerable length, were emitted, whilst no sensible 

 growth took place between the base of the young shoots and the mould 

 in the pots. 



It having been proved by Duhamel that inverted parts of trees 

 readily emit roots, I expected to derive further information from cuttings 

 of this kind : I therefore planted, in the autumn of 1802, forty cuttings 

 of the gooseberry-tree, and an equal number of the common currant- 

 tree ; one half of each being inverted. Of the former, not one of the 

 inverted cuttings succeeded ; whereas few of the latter failed ; and in 

 these I had an opportunity of observing the same accumulation of wood 

 above the bases of the annual shoots, and the same mode of growth, in 

 every respect, as in the inverted vines ; except that no roots were 

 emitted at their upper ends. The same thing occurred, without any 

 variation, in inverted grafts of the apple-tree. 



If it be admitted, according to the theory I have on a former occasion 

 laid before you, that the sap descends from the leaves through the vessels 

 of the bark ; and that such vessels are, in their organisation, better calcu- 

 lated to carry their contents towards the original roots than in the 

 opposite direction ; it will be extremely easy to explain the cause of the 

 accumulation of wood, and the emission of roots, above, instead of below, 

 the base of the annual shoots. The vessels of the bark (the vaisseaux 

 propres of Duhamel) commencing in the leaves, were formerly traced 

 by M. Mariotte, and subsequently by myself, (being ignorant of his 

 discovery,) to the extremities of the roots ; and when a cutting, or tree, 

 is planted in its natural position, the sap passes downwards through these 

 to afford matter for new roots, and to increase the bulk of those already 

 formed, having given proper nutriment to the branches and trunk in its 

 descent. But, in the inverted cutting, or tree, these vessels become 

 inverted; and, if their organisation be such as I have supposed it, a 

 considerable part of -that fluid, which naturally descends, will be carried 

 upwards, and occasion the production of new wood, above, instead of 



