Snake venoms : their physiological action and antidote / by George Lamb.

  • Lamb, George, 1869-1911.
Date:
[1903]
Catalogue details

Licence: In copyright

Credit: Snake venoms : their physiological action and antidote / by George Lamb. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    or of that of the echis, nor do I know of any thoroughly trustworthy scientific observations which have been made with the poisons of these two species. And let it be clearly understood that, although the kraits and the king cobra are colubrine snakes, and echis a viper, it by no means follows, as I have good reason to know, that the poisons of the krait Eamily and of the king cobra have the same physiological action as the venom of the cobra, or that of the echis the same as the venom of the daboia, nor even that the poison of one variety of bungarus is the same as that of another variety of the same family. The poison of snakes is secreted by two glands, one on each side of the head. These glands are the homologue of the parotid salivary glands of other vertebrates. They are situated behind the orbit, quite superficially beneath the skin. They are, in the case of the cobra, about the size of, and somewhat resemble in shape, an almond. Each gland is enclosed in a dense fibrous capsule. This capsule serves as an attachment to the muscle, which, as we shall see, compresses the poison out of the gland. The muscle is the masseter muscle. It assists powerfully in closing the lower jaw. In a dissected specimen, you will see that it is divided into two portions. The upper portion, arising from the skull along a curved line behind and above the orbit, passes downwards and backwards to be inserted along the upper and posterior margin, as well as to the external surface of the capsule; it envelopes the gland above and behind. The lower portion arises from the internal surface of the gland capsule at the back part, and, widening out, passes down to be inserted into the lower jaw. When this muscle contracts, as it does power- fully when the snake closes its jaws on its prey, you will understand how the, poison gland is, as it were, forcibly wrung between these two portions of the muscle, much in the same way as a housewife wrings a wet cloth between her hands. In this way, the poison is ejected into the duct at the right moment, viz., when the fangs are buried and ready to convey the death-dealing dose. From the front portion of the gland, the poison duct passes Forward, runs along the lower margin of the orbit, and opens on the top of a small papilla, which is aituated at the base of the Eang on the anterior wall of a sheath of mucous membrane, which embraces the Eang. This duel, therefore, is aot directly continuous with the canal of the poison Eang. I regret that time does not permit of me explaining to you how Lt comes about that no leakage of the poison takes place at this junction. A2