Serpents' venom : artificial and natural immunity : antidotal properties of the blood-serum of immunized animals and of venomous serpents / by Thomas R. Fraser.

Date:
1895
Catalogue details

Licence: Public Domain Mark

Credit: Serpents' venom : artificial and natural immunity : antidotal properties of the blood-serum of immunized animals and of venomous serpents / by Thomas R. Fraser. 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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    however, that protection lasts for at least a considerable period of time, even when the last protective dose has not been a large one. For example, to a rabbit which had last received twice the mini- mum-lethal dose of Crotalus venom, the same dose was administered twenty days subsequently, and it altogether failed to produce any toxic symptoms. Before passing to the next part of my communication, it may be stated that as yet no sufficient data have been obtained for affording an explanation of these remarkable facts. It is obvious that the blood of protected animals must contain some substance or sub- stances which are not present in the non-protected animals, by which the lethal and toxic effects of venoms are prevented. I have observed that when the blood-serum of protected animals is added to a solution of venom, a distinctly observable reaction occurs, and this reaction may be of significance when considered along with circumstances, which will be stated in the remaining part of this communication, and especially with the circumstance that the blood-serum itself possesses but little physiological activity. This protective substance may be produced in the body by the influ- ence of the venom, but it is also conceivable that the substance is actually a part of the venom itself, which gradually accumulates under repeated administrations, whereas the lethal and toxic con- stituents of the venom are more rapidly destroyed or eliminated. 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 this Society 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 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 properties are possessed even by this serum. It soon became apparent that in order to obtain some reasonable approximation to constancy in the conditions of the experiments, it was necessary