40 ME. SOLLY ON THE POTATO MUBRALV, 



published early in September,* as to the proximate cause of the 

 disease, and which in several points resembles that published by 

 Dr. Lindley in August. I believe the disease was caused by the 

 presence of putrefying azotised matter in the stem, just below the 

 surface of the soil ; the natural circulation of the fluids of tiie plant 

 carried this ferment, for such we may term it, to all parts of the 

 plant, causing throughout a struggle between the vital force and 

 the chemical force of fermentation, or induced decomposition. 

 That the change was really one of tlds kind, and not a mere effect 

 of oxidation, is proved, I tliink, by the fact tliat tlie disease com- 

 menced and proceeded quite independent of external oxygen. 

 Assuming for granted the truth of this view, it still remains to 

 account for the presence of putrid matter in tlie interior of the 

 plant. Although no similar epidemic has been observed amongst 

 plants in any previous year, yet we cannot say that it is alto- 

 gether new and unprecedented ; precisely the same disease has 

 been observed in previous years, although never to the same ex- 

 tent, and numerous isolated cases might be quoted, in which po- 

 tatoes, and also other plants, liave suffered from a similar cause. 

 A strong case of this kind came under by own observation in the 

 summer of 1843. A small field of turnips, in the Horticultural 

 Society's Gardens, which had been manuied with Aarious saline 

 substances in strips or b(ds, and which was growing most luxu- 

 riantly, was observed at the end of August, when the bulbs were 

 about half formed, to have received some sudden check ; the 

 tops gradually became yellow, and at the same time the bulbs 

 softened and putrefied, the rot generally commencing in the 

 centre and spreading all round. Towards the end of September 

 at least -two thirds of the crop were thus lost, and this certainly 

 amounted to some thousand turnips. It was at first thought that 

 the manures used might have caused the rot, but examination 

 showed that those not manured at all were among the first to go. 

 These turnips, when compared with those of the previous year, 

 were foinid to contain an unusually large proportion of water, as 

 the following table shows : — 



White globe turnip, 1842 

 DiUo 1843, mauure sulph. lime 

 Ditto 1843, no manure 

 Ditto 1843, manure, sulph. potash 

 Ditto 1S43, mauure, mur. potash 



The second and third were perfectly fresh at the time of examining 

 them, the two last were taken as having just commenced to change. 



* Gardener's Chronicle, September 20. 



