PART I. 

 PAPERS ON VEGETABLE PHYSIOLOGY, 



READ BEFORE 



THE ROYAL SOCIETY, IN THE YEARS 1795 TO 1816. 



REPRINTED FROM THE PHILOSOPHICAL TRANSACTIONS. 



I. OBSERVATIONS ON THE GRAFTING OF TREES. 



[Read before the ROYAL SOCIETY April 30th, 1795.] 



THE disease from whose ravages apple and pear trees suffer most is the 

 canker ; the effects of which are generally first seen in the winter, or 

 when the sap is first rising in the spring. The bark becomes discoloured 

 in spots, under which the wood, in the annual shoots, is dead to the 

 centre ; and, in the older branches, to the depth of the last summer's 

 growth. Previous to making any experiments, I had conversed with 

 several planters, who entertained an opinion, that it was impossible to 

 obtain healthy trees of those varieties which flourished in the beginning 

 and middle of the present century, and which now form the largest orchards 

 in this county (Herefordshire). The appearance of the young trees, which 

 I had seen, justified the conclusion they had drawn ; but the silence of 

 every writer on the subject of planting, which had come in my way, 

 convinced me it was a vulgar error, and the following experiments were 

 undertaken to prove it so. 



I suspected that the appearance of decay in the trees I had seen lately 

 grafted, arose from the diseased state of the grafts, and concluded that 

 if I took scions or buds from trees grafted in the year preceding, I should 

 succeed in propagating any kind I chose. With this view, I inserted 

 some cuttings of the best wood I could find in the old trees, on young 

 stocks raised from seed. I, again, inserted grafts and buds taken from 

 these on other young stocks, and, wishing to get rid of all connexion 

 with the old trees, I repeated this six years ; each year taking the young 



