238 TIMBER AND SOME OF ITS DISEASES, [chap. 



over, as already stated, it has been shown by 

 experiments that the spores will infect the stem 

 of the larch if they are introduced into a wound ; 

 but it is important to notice that the fungus cannot 

 penetrate the sound cortex. 



It now remains for us to see if, in the natural 

 course of events, infection of the larch can take 

 place to any great extent ; for, unless this is the 

 case, we cannot reconcile the above peculiarities of 

 the fungus with the prevalence of the disease. 



It must be borne in mind that the larch is an 

 Alpine tree, growing naturally at an elevation of 

 from about 3000 to 6000 feet above sea level, and 

 even more. In its native heights, both the larch- 

 disease and Peziza Willkommii occur associated as 

 we have described them, but the malady does not 

 become epidemic, as it has done in the valleys and 

 plains of Europe. 



Several insect-enemies of the larch arc known, 

 some of which feed on the buds, and others on the 

 leaves, &c. : it is not impossible that insect-wounds 

 may serve occasionally as points of entry for the 

 fungus. 



But attention should be directed to the remark 

 made when describing the symptoms of the disease — 

 namely, that a dead branch often springs from near 



