578 Causes of Disease iti the Larch. 



the larger kinds of the natural shrubs were growing, so as to 

 render a clearing of them necessary, preparatory to the planting 

 of the larches ; in no one of these different plantations has dis- 

 ease been detected; while, on the other hand, in plantations 

 formed subsequently to this date, and where plants of an earlier 

 age have been adopted, and the slit mode of inserting them 

 practised, failures have taken place, not only about Dunkeld, 

 but in many other situations throughout the country. 



There is a class of planters who attribute the present un- 

 healthy condition of our larch plantations to atmospheric in- 

 fluence ; an opinion grounded upon the sickly appearance which 

 the plants, in many instances, exhibit in the course of the spring 

 and summer months. Only a moment's reflection is necessary 

 to explode this vague notion. We have now a numerous family 

 of half-hardy trees and shrubs exposed to our variable climate, 

 and it sometimes happens that these are partially injured by the 

 severity of our winters. I remember a severe visitation of frost, 

 upon the night of the 28th of May, some sixteen or eighteen 

 years ago, which killed all the new-formed wood of an extensive 

 collection of American and other shrubs ; and even the hedges 

 of beech suffered, as if by fire : yet these all recovered, and 

 became good healthy plants afterwards. Now, should the larches 

 suffer, at any time, by a similar visitation (as some affirm they 

 did in 1801 or 1802), might we not reasonably expect that they, 

 like other exotic plants, would resume their wonted verdure in 

 the course of the following summer ? Certainly they would. 



I can see no good grounds for supposing that, when the larch 

 exhibits a sickly hue and withered spray, this effect proceeds 

 altogether from external agents : on the contrary, I think it is a 

 consequence arising from previous internal disorganisation. I 

 may here submit the same argument to those who imagine, with 

 as little reason on their side, that the evil may be traced to the 

 attacks of insects. In animal, as well as in vegetable subjects, it 

 is seldom seen that those in robust health become the prey of 

 vermin : and, therefore, we may rest satisfied that, whenever an 

 attack is made by insects, it is an effect of a cause whose seat lies 

 deeper than the surface. 



With regard to the importation of seeds from the larch tree's 

 native country, as a means of securing healthy larches, one esta- 

 blished fact has come under my own observation, which, so far 

 as it goes, suggests that we have very little to hope for from 

 importation. About three weeks ago, a friend informed me 

 that, upon the princely domain of Sir James Carnegie, Bart., of 

 South Esk, there were a few larch trees growing, that were 

 raised in this gentleman's private nursery from seeds imported 

 from Switzerland ; and which were alike the victims of disease 

 with those raised, from seeds of home growth. I, on learning 



