46 JOURNAL OF THE EOYAL HORTICULTUKAL SOCIETY. 



•when scions had been sent him to graft with they were often 

 cankered, in which case the growth always kept cankered ; but 

 if one healthy bud could be found on the scion, and was trans- 

 ferred to a Paradise stock, it would be perfectly healthy, and 

 seemed to rejoice in the fresh blood. The old Ribston, again, 

 used to be noted for canker, but anyone might examine whole 

 breadths of it now in his nursery and they would not find any 

 canker where they were worked on the Paradise stock. He 

 believed that those sorts and varieties which had the largest 

 wood cells were the most easily hurt by the frost and induced to 

 canker, the cells being ruptured through the excess of moisture 

 that they contain. 



Mr. Cheal considered it to be most important to select 

 thoroughly healthy trees from which to take grafts. He had 

 been able to obtain a perfectly healthy stock of Ribstons by 

 always selecting the healthiest grafts and the healthiest stocks, 

 and in this way he had almost eradicated the disease. 



Mr. Feaser said there could be no doubt that as certain 

 diseases in animals were due to disease' germs, so it was also 

 with plants. A German savant had shown that a particular 

 fungoid growth was always to be found in specimens of canker ; 

 he had also experimented with the germs of this fungus, growing 

 them in some sort of broth, and then had inoculated trees with 

 the product, and every one of the trees cankered. The name of 

 the fungus was, he believed, Nectria ditissima, the same as was 

 often found in the ash and the beech, and can be communicated 

 from them to the apple and pear. They would probably all 

 agree that fruit trees required feeding, and if the feeding did not 

 destroy the disease it would at least help them to resist it, or 

 assist them in throwing it off. 



Mr. ToNKS thought that Mr. Bunyard's remarks quite con- 

 firmed his experience, viz., that trees will grow well and bear 

 well for a certain number of years and then become cankered. 

 They do find sufficient root food for a time, but when it is ex- 

 hausted canker is sure to ensue. With regard to the bacteria germ 

 theory, no doubt it was just now very popular, and for anything he 

 could tell bacteria might be at the bottom of many diseases, but 

 the highest authorities are by no means agreed on the subject 

 as yet — one man always finds what another equally clever cannot. 

 Moreover, individual experiments are extremely unreliable, and 

 do not deserve much attention until they have been confirmed by 

 several independent observers. He was not prepared to deny the 

 experiments that had been referred to, but he thought they were 

 at least liable to the possibility of mistake, and he was not pre- 

 pared to admit on such evidence that all canker was due to some 

 low form of fungoid disease. The great advantage of his own 

 remedy was that if it did not cure the canker it would do the 

 trees good ; it could do no harm, and it might do much good. 



