§ 645. Detection of the Cobra Venom.—In an experiment on a rabbit, the animal was killed by the subcutaneous injection of 8 mgrms. per kilo. of the cobra poison. Immediately after death, 2 c.c. of the blood were injected into a small rabbit; in fifteen minutes there was slow respiration with pains in the limbs; in thirty minutes this had, in a great measure, passed off, and in a little time the animal was well. In any case in which it is necessary to attempt to separate the cobra venom, the most likely method of succeeding would be to make a cold alcoholic extract, evaporate in a vacuum, take up the residue in a little water, and test its effect on small animals.
§ 646. Duboia Russellii.—The Duboia russellii or Russell’s viper is one of the best known and most deadly of the Indian vipers. The effects of the poison of this viper are altogether different from those of the cobra. The action commences by violent general convulsions, which are often at once fatal, or may be followed by rapid paralysis and death; or these symptoms, again, may be recovered from, and death follow at a later period. The convulsions do not depend on asphyxia, and with a small dose may be absent. The paralysis is general, and may precede for some time the extinction of the respiration, the pupils are widely dilated, there are bloody discharges, and the urine is albuminous. Should the victim survive the first effects, then blood-poisoning may follow, and a dangerous illness result, often attended with copious hæmorrhages. A striking example of this course is recorded in the Indian Med. Gaz., June 1, 1872.
A Mahommedan, aged 40, was bitten on the finger by Russell’s viper; the bitten part was soon after excised, and stimulants given. The hand and arm became much swollen, and on the same day he passed blood by the rectum, and also bloody urine. The next day he was sick, and still passing blood from all the channels; in this state he remained eight days, losing blood constantly, and died on the ninth day. Nothing definite is known of the chemical composition of the poison; it is probably qualitatively identical with “viperin.”
§ 647. The Poison of the Common Viper.—The common viper still abounds in certain parts of Great Britain, as, for example, on Dartmoor. The venom was analysed in a partial manner by Valentin. In 1843 Prince Lucien Bonaparte separated a gummy varnish, inodorous, glittering, and transparent, which he called echidnin or viperin; it was a neutral nitrogenous body without taste, it arrested the coagulation of the blood, and, injected into animals, produced all the effects of the bite of the viper. Phisalix and G. Bertrand have studied the symptoms produced in small animals after injection. A guinea-pig, weighing 500 grms., was killed by 0·3 grm. of the dried venom dissolved in 5000 parts of saline water; the symptoms were nausea, quickly passing into stupor. The temperature of the body fell. The autopsy showed the left auricle full of blood, the intestine, lungs, liver, and kidneys injected. The blood of the viper is also poisonous, and produces the same symptoms as the venom.[652] The same observers have shown (Compt. rend., cxviii., Jan. 1894) that the blood of the water-snake (Tropidonotus natrix) and of the Thuringian adder (Tropidonotus viperinus) is poisonous, producing the same symptoms as that of the viper.
[652] Compt. rend. Soc. de Biol., t. v. 997.
The Venom of Naja Haje (Cleopatra’s Asp).—It has been stated that 20,000 persons annually die in Ceylon from the bite of Cleopatra’s asp. Graziani (Rif. Med., October 7, 1893) has undertaken a physiological study of the venom, which has already received attention at the hands of Calmette, Wall and Armstrong, Weir Mitchell, Reichardt, and others. The venom, when dried, appears as transparent scales, easily soluble in water, very slightly so in alcohol, ether, or chloroform; its aqueous solution has an unpleasant odour, and is neutral to test paper. Chemically it gives all the tests described by Weir Mitchell and others as characteristic of the venom of Naja tripudians. The physiological effects of this dried venom were tried on guinea-pigs, rabbits, and frogs, to all of which it proved fatal in extremely minute doses. The guinea-pig, a few seconds after injection, becomes paralysed in its hind limbs, it foams at the mouth, and makes violent attempts at vomiting. The eyes are half closed, but occasionally for short periods there is a partial disappearance of the paralysis, and the animal makes feeble attempts to support itself. Respiratory embarrassment is soon added to the foregoing symptoms, and the animal lies perfectly prone, devoting all its attention to breathing, which is rendered still more difficult by the vomiting and frothy saliva which is secreted in abundance. Finally death ensues from asphyxia. The post-mortem examination reveals the heart still feebly beating, the lungs pallid, and the blood in the organs very dark. The liver and kidneys are hyperæmic, but the brain and cord, with their coverings, are anæmic. In the rabbit the course of the poisoning is practically identical with that described above. Histologically, the following facts are made out in addition to the foregoing. The red blood-corpuscles are in great measure broken down, and there are also effusions into the muscular tissues. The kidneys are very hyperæmic, and there is marked degeneration of the epithelium lining the glomeruli and convoluted tubules. The glomerular capsules are much distended, and numerous leucocytes are discernible throughout the organ. The liver, also, is hyperæmic, and shows numerous broken-down blood-corpuscles, and partial necrosis of many of the liver cells. Examination of the central nervous system reveals no particular changes.