Immunisation against serpents' venom and the treatment of snake-bite with antivenene / an address delivered by Professor Fraser on Friday, March 20, 1896.

Date:
1896
Catalogue details

Licence: Public Domain Mark

Credit: Immunisation against serpents' venom and the treatment of snake-bite with antivenene / an address delivered by Professor Fraser on Friday, March 20, 1896. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    venom, even fifteen times larger than the minimnm-lethal, may be administered without producing more than an inconsiderable degree of local destructive effect. Experiments have also been made by which it has been demon- strated that when an animal has acquired a resistant power over the minimum-lethal dose of one venom, that animal is also able success- fully to resist the lethal action of a dose above the minimum-lethal of other venoms. To a rabbit protected against cobra venom, a dose above the minimum-lethal of Sepedon venom has been administered ; to rabbits protected against Crotalus venom, doses above the mini- mum-lethal of Diamantina and of cobra venoms have been given ; to rabbits protected against the Diamantina venom, doses above the minimum-lethal of Crotalus and Sepedon venoms have been given; and in each case the animal has recovered, and but few symptoms of injury were produced. At the same time, in other experiments, indications were obtained that animals protected against a given venom are capable of resisting the toxic effect of that venom more effectually than the toxic effect of other venoms. The experiments have not yet proceeded sufBciently far to show for what length of time the protection conferred by any final lethal dose may last. It has been discovered, however, that protection lasts for at least a considerable period of time, even when the last protec- tive dose has not been a large one. For example, to a rabbit which had last received four times the minimum-lethal dose of cobra venom, twice the minimum-lethal dose was administered thirty-four days subsequently; while to another rabbit, which had last received twice the minimum-lethal dose of Crotalus venom, the same dose of this venom was administered twenty days subsequently, and in each case the second dose failed to produce any toxic symptom. Having thus succeeded in producing a high degree of protection in animals against the toxic effects of serpents’ venom, the blood-serum of these animals was, in the next place, collected for the purpose of testing its antidotal properties. In this portion of the investigation, the method followed was essentially the same as that described in a communication made by me to the Eoyal Society of Edinburgh in 1871, on “ The Antagonism between the Actions of Physostigma and Atropia,” as it appeared to be the most direct method for obtaining accurate knowledge of the value of an antidote. A few preliminary experiments were, however, early made with the serum of animals in whom the protection had not been carried to a high degree, and they were sufficient to show that antidotal proper- ties are possessed even by this serum. It soon became apparent that in order to obtain some reasonable api)roximation to constancy in the conditions of the experiments, it was necessary that the serum should be in such a state that it would remain unchanged during at least several weeks. It was found that this could be insured, without any appreciable loss of antidotal power, by drying the freshly-separate* I scrum in the receiver of an air-pumj) over sulphuric acid.