334 
amongst trees growing in wet, low-lying districts ; and when 
seeking information from foresters and others interested in such 
matters, they have invariably attributed it to dampness of situation. 
he disease is caused by minute insects, and not as some have 
thought, by a species of fungus. The trunk of the tree is first 
attacked, and while some portions of it to all appearance remain in 
a healthy state, those which the insects infest gradually assume a 
dry appearance and when closely examined, the bark will be found 
to separate from the wood, and become dry and lifeless. Other 
unfavourable influences may, of course, favour the speedy decay of 
the tree, but it soon becomes evident that future healthy develop- 
ment is arrested, and when the trees are cut down, the ravages 0 
the insects cease with the life of the bark. This is, I think, the 
most curious circumstance connected with the disease and may 
under careful investigation go some length to make us acquainted 
with means to effect its destruction. While the ravages of the 
the beech are in some places affected with a disease to all 
appearances similar ; as for example, the silver firs on the estate of 
Dunmore near Stirling. Amongst the many plans adopted here, 
the only one that has succeeded to any degree is that of brushin 
with a hard brush, the parts infected, when the bark is dry.” 
In the same journal at pp. 267-268, of the same year, attention is 
directed to a peculiar diseased condition of beeches at Tyninghame 
and Meilerstain, estates of the Earl of Haddington, in a letter from 
the Earl to Prof. Balfour, which was read at a meeting of the Society. © 
The stems are said to be covered by a cottony matter, an 
the Earl wished to know whether it killed trees, or whether 
it only appeared on trees in failing health, for in every case 
affected trees died. In some instances the whole tree was covered 
and in others one side o He had written to Mr. Hardy 
of Penmanshiel, who had replied that the insect was Coccus fagi, 
and gave an account of a former case noticed at Dalkeith, and also 
said that it occurred near London. In the discussion which 
followed, Mr. W. R. McNab remarked that Mr. McIntosh had 
noticed a similar diseased condition of the beech trees in Dalkeith 
g> 
British Agriculturist. He seems to have considered it a fungus. 
Mr. McNab thought that the Coccus only appeared on trees which 
were already in an unhealthy condition. Dr. Balfour stated that 
the same species of Coceus had destroyed some beech trees in the 
Botanic Garden, Edinburgh, which had been planted very closely 
and were hemmed in by other trees and shrubs. 
In the “ Gardeners’ Chronicle” for August 19th, 1865, p. 776, 
M. J. B, [Berkeley], replying to E. T., aye about the Cocks that 
it has been called a fungus, Psilonia nivea, but is an insect, and 
appears frequently on the bark of living trees, but that it was not 
known to cause death.” He adds that “the drought of the 
previous year had been fatal to many trees which were in an 
