New theory and old practice in relation to medicine and certain industries : being an analysis of current literature of these subjects / by C.A. Gordon.

  • Gordon, Charles Alexander, 1821-1899.
Date:
1886
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Licence: Public Domain Mark

Credit: New theory and old practice in relation to medicine and certain industries : being an analysis of current literature of these subjects / by C.A. Gordon. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    that the appearance of the phylloxera is always preceded by a diseased condition affecting the condition of the root of the plant, and characterized by definite anatomical appearances (described by him in the Journal d'Agriculture Prat'ique, April 16, 1885); consequently that the phyl- loxera is itself a sequence of that diseased condition. M. Hamoir, a practical agriculturist, observed that in the north of France the field-bean had ceased to yield its flower and fruit, that it had run to leaf, that the leaves rapidly became attacked by vermin, and fell off decayed. He concluded from that circumstance that the fault existed primarily in the nature of the manure used. It is Avell known that nitrogenous substances tend especially to the production of leaves, cal- careous matters to that of fruit; hence due equilibrium between those elements must be maintained. The free use of phosphate of lime, which M. Hamoir recommended in the case of the diseased beans, is no less suitable in that of the diseased vine and all other plants which yield saccharine productions. It is pointed out that if a healthy young apple, tree be transplanted into unsuitable soil tlie bark will speedily become covered with lichens and mosses. By and bye theorists Avill see in these parasitical plants the cause of the deteriorated condition of the plant, not in the fact of the soil being unsuitable to its requirements. MM. Joulie and ViUe have pointed out that the vine requires for its regular and normal development, and consequently for its healtliy condition, a soil contaming in proper proportions j^hosphoric acid, potass^ lime, and magnesia, while nitrogenous elements must be in moderate quantity. Such is the condition of the soil in the Marne district, and there the vine does not suffer from the phylloxera. It equally resists the microbes of oidium, pernospora, and of a crowd of other diseases which according to the modern school float continually over and around thcni. Here, then, is an explanation of the vine disease ; it does not prevail in localities where the soil is calcareous; it does prevail wherever the soil is azotised, such as the valley of the Ehone, formed by alluvium of the xVlps. Fifty years ago M. J. B. Dumas taught that the value of a manure was ' in proportion to the nitrogen contained in it. His theory was at once accepted, and thenceforward artificial azotised manure was extensively made use of, not only for the vine but also for beet-root cultivation, 'ihe consequence was that crojDS in abundance were obtained, but a gradual diminution took place in the mineral elements necessary for vegctatitm, the formation of which in the sub-soil lakes place very slowly; tliat