the blisters when the trees recover health and vigour; and he mentions a plantation over twenty years old, more or less mixed with beech, on greensand, Where a mumiber of old blisters are gradually becoming occluded. That they were genuine blisters is evident from the remains of the Peziza cups still present, and the only possible theory respecting their disappearance must be found in the improved health of their host. I have frequently observed similar cases, both on my own land, where in some of the worst diseased plantations, individual trees, which on account of their greater vigour have taken a lead from the first, remain almost untouched and growing vigorously, when most of the surrounding trees are killed or severely injured; and also in Hertfordshire, where tall slender larch trees growing amongst beech showed at various points, from near the ground up to 50 or 60 feet, signs of repeated attacks, which had neither killed them nor apparently checked their growth materially. Forbes says that one may pick up dead twigs or branches under the largest, finest, and most isolated larches that can be found, and the fructifications of Peziza are invariably present on them. This fact he thinks is sufficient to prove that the mere existence of the fungus does not necessarily lead to diseased trees, using the term diseased in its practical sense.
The year 1879 will long be remembered by all gardeners, farmers, and landowners in the southern half of England as the most disastrous in its effects on plants, farm crops, and trees generally. There was practically no summer, and the rainfall was so continuous, that in late districts much of the corn never ripened at all, and being followed by two severe winters, the disease spread to a degree which ruined hundreds of acres of young larch on my own estate, and caused a loss which must have amounted to millions of pounds throughout the whole country. Though after bad seasons and in smaller areas there had been disease before, it was generally assumed by planters that larch might be successfully grown on almost any kind of land without mixture, and without any special precautions, and there is little doubt in my mind that a large percentage of the worst cases originated in that season, and may be directly traced to the exceptionally bad climatic conditions which prevailed.
Mr. A. M'Dougal, forester to the Earl of Feversham at Helmsley in Yorkshire, who has charge of something like 10,000 acres of woodland, and, having been brought up on the Duke of Atholl's estate, has had unusual experience of the larch, tells me that in Yorkshire the disease first began to be prevalent about 1862 when two plantations died clean off. Since then it has been very prevalent on thin red loam overlying limestone rock; and this applies as much to localities which have previously been under oak wood, or cultivation, as to those where larch has been replanted after larch. He considers that severe spring frosts, together with lowlying situations and heavy soil, are the conditions which bring on the disease most severely.
Sir W. Thiselton Dyer, who has been good enough to read this article, does not quite agree with me with regard to the disease, which he considers due to physical causes alone, and not influenced by heredity. He says that the fungus is a wound parasite, whose spores can only develop in lesions where the bark is injured either
