SCIENTIFIC COMMITTEE. SEPTEMBER 2. 



cxlix 



Twin Cucumbers. — A specimen of this not uncommon peculiarity was 

 exhibited by Lady Laura Hampton. The appearance is probably due to 

 the union of two flowers in a very early stage of their development. 



Cracked Pears. — Specimens were shown showing the effect of Fusi- 

 cladium in arresting the growth of the rind of the Pear, which, being 

 unable to expand, cracks as the flesh beneath increases in bulk and exerts 

 pressure upon it. Spraying in an early stage is the only means of pre- 

 venting the mischief. 



White Heather. — Mrs. Streatfield sent specimens of the white variety 

 of Erica Tetralix from a Surrey common. 



Silver-leaf Disease. — A letter was read from Prof essor Percival relating 

 to the specimen forwarded to him from the previous meeting :— " From 

 sections of the stump through the points of union of scion and stock, it 

 seems very probable that the fungus which causes the disease had entered 

 at the point of grafting in this particular case. Such examples are not 

 at all uncommon, although in many cases the disease starts in the roots 

 below ground. The disease, I have abundantly proved this year in my 

 own garden, can be induced with the greatest ease by inoculating any part 

 of the tree either above or below ground. The fungus (Stereum pur- 

 purewm) does not itself extend very far in the tissues of the diseased 

 trees, but some of its products, or products resulting from its action on 

 the tissues of the trees, circulate rapidly in an upward direction, and 

 induce the peculiar changes in the leaves. Downward circulation also 

 takes place, but much more slowly. In several cases of inoculation with 

 the fungus on long branches of plants, the disease has spread downwards 

 even after the greater portion of the branch has been cut away at a point 

 several inches below the point of inoculation." 



Copper as a cause of Yellow Foliage. — Mr. Gaut alluded to the yellow 

 tint assumed every year by the foliage of certain Apple-trees and Rasp- 

 berry bushes near Richmond, in Yorkshire. The want of green colour 

 had been attributed to the presence of copper in the soil, but as it was 

 considered that the evidence in support of this opinion was inadequate, 

 further information was solicited. 



Melon Disease. — Mr. Willard sent specimens of this disease, charac- 

 terised by rotting of the bine, and conjecturally attributed to the presence 

 of bacteria. Acting on a suggestion of Dr. Masters, Mr. Willard had 

 inoculated a seemingly healthy plant with some of the juice from a 

 diseased plant. The result was the development of disease within a very 

 short time. The Committee, however, thought the result of the infection 

 would not have manifested itself so rapidly, and that the inoculated plant 

 would shortly have shown symptoms of the disease, even if it had not 

 been inoculated. Further experiment was suggested. 



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