Report on experimental investigations upon the intimate nature of the contagium in certain acute infective diseases / by G.F. Dowdeswell.

  • Dowdeswell, G.F.
Date:
1884
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Licence: Public Domain Mark

Credit: Report on experimental investigations upon the intimate nature of the contagium in certain acute infective diseases / by G.F. Dowdeswell. 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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    tion is admitted, and the paradoxical conclusion arrived at (loc. cit., Erzugung, etc., p. 152 et seq. and p. 170 ib.), that the oxygen of the atmosphere is the agent both by which the fatal contagium of anthrax is deprived of its virulence, and also by which the innocuous saprophyte, fancifully, in opposition to the generally accepted nomen- clature of Cohn, termed by the author “bacterium” subtile, in an inverse process of cultivation, loses its mobility, and^ecomes the virulently infective bacillus anthracis.15 It must, however, be admitted that, while, as stated, the observa- tions here in question can establish nothing, whatever may be the fact as to the mutability of species, morphological or physiological, in these organisms, the occurrence of protective inoculation by certain, though not as yet clearly defined, methods of cultivation, which appears to be established by the extensive series of experiments recently recorded, involves a modification of virulence, an alteration of physiological function, in the organism ; and that, consequently, the views of Cohn and his school as to the constancy and immutability of species in the lower fungi cannot be maintained in their entirety.16 The first recorded experiments upon putrid poisoning or septic infection are generally credited to Gaspard, who, in conjunction with Majendie,17 tried the effects of injecting a great variety of substances, septic and other, into the blood-vessels of living animals, but without obtaining any very definite results ; though, previously, Haller,18 had shown, in 1765, that putrid water injected into the blood of living animals was toxical. Leuret,19 however, was the first who proved by experiment that the blood of an infected animal was itself infective when injected into another. His experiments were made chieHy upon cases of charbon (anthrax), which he attributed to a putrid—chemical —poison ; he has the merit, too, of having conclusively shown that the blood in such cases decomposes more readily than that of healthy animals. MM. Coze and Feltz20 greatly extended these experiments, about the year 1866, in France, showing more particularly, by numerous experi- ments, that when certain animals are intoxicated by the injection of septic matter, their blood becomes infective to others. Further, they asserted that, in successive inoculations from one animal to another of the same species, such blood acquires an increase of infective virulence. 15 The method, too, here described as employed for obtaining the infective matter with which to originate the cultivations, viz., by triturating a portion of the spleen of an infected animal in 'an open mortar, without any precautions against atmo- spheric contamination, could have but one result, as is well known to every one who has made any such experiments. 16 I may here add briefly, with respect to the question of the morphological transformations of these organisms, that while, obviously, certain species pass through a wide cycle of different phases in their life-history, as, e.g., in the case of Beggiatoa roseo persicina, described by Professor E. Ray Lankester (Quarterly Journal of Microscopical Science, 1873, etc.) and some others; yet that there is no reason to doubt the constancy of such species, or to suppose that all the different forms that occur are merely phases of one and the same species, any more than to assert this in the case of all insects, which in their life-cycle pass through various transformations ; others, too.are “ Protean and adaptive” in their transformations, the forms they assume being' controlled by alterations in external conditions ; the Bacillus anthracis was shown by Toussaint (Recherches sur la Maladie Charhonnevse. Lyons, 1879) to assume various abnormal forms in certain methods of cultivation, this has quite recently been confirmed and extended by Dr. Klein in this country. (Report of Medical Officer to the Local Government Board, 1882-83, and Quarterly Journal of Microscopical Science, 1883). 17 Journal de Physiologic de Magendie, t. 2, s. 4, 1822 and 1S23. The work is somewhat scarce, though in the University Library at Cambridge ; but its interest is chiefly historical. 18 Elementa Physiologke, Gottingen and Leyden, 1765, vol. iii, p. 154, etc. i® Recherches et Experiences sur TAlteration dn Sang, par M. Leuret, M.D., Arch. Gen. de Medecine, Paris, 1826, p. 98. 2® Recherches Cliniques et Kxptrimentqies sur let Maladies Infectieuses, Strashnrg and Paris, 1866 and 1872. The work is interesting in many respects. There is. a copy in the Library of the Royal Medical and Chirurgical Society.