ARE VENOMOUS SNAKES AUTO-TOXIC? AN INQUIRY INTO THE EFFECT OF SERPENT-VENOM UPON THE SERPENTS THEMSELVES . BY Surgeon L. A. WADDELL, M.B., DEPUTY SANITARY COMMISSIONER, BENGAL. CALCUTTA : PRINTED BY THE SUPERINTENDENT OF GOVERNMENT PRINTING, INDIA. 1889. Reprinted from Vol. IV, “Scientific Memoirs by Medical Officers of the Army of India*” 3 CONTENTS INTRODUCTORY. Page Practical bearing of inquiry ............ 3 Seeming anomaly of subject ............ 3 Conflict of opinion on question ........ ...3 Favoring view of insusceptibility .......... 3 In favor of susceptibility ............ 4 Mixed views .............. 4 Desirability of further investigation ...5 PART I. Working Scheme adopted. Scope of inquiry defined 5 Sources of Experimental Error ............ 5 Injury to viscera, &c., during infliction of bite ........ 5 Uncertain introduction of venom by biting ......... 5 Frequent mortality of captive snakes . . . . . . . . . .6 Necessity for prolonged observation .......... 6 Using venom of unascertained activity ......... 6 Precautions taken .............. 6 PART II. Effect of Venom on Serpent itself or its own Species. The Experiments 7 General arrangements ............ 7 Details of Experiments . . . . . . . . . . . .7 First Series of Cobras , Experiments I to XII . ....... 7 Second ditto, Experiments XIII to XIX ....... 10 Third ditto. Experiments XX and XXI . . . . . . .12 Results of these experiments . . . . . , . . . . . .13 Mitchell’s and Fayrer’s experiments reviewed in the light of these results . . . .13 Fayrer’s anomalous experiments . . . . . . . . . ■ , -13 Mitchell’s ditto ditto ........... 14 Mitchell’s inference scarcely warranted ......... 15 General conclusion on the auto-toxicity of snakes ......... 13 CONTENTS. PART III. Effect of Venom on Venomous Snakes of other Species. Page Experiments on Trimeresuri with Cobra-venom . . . . . . . . . 15 Effect of Cobra, Daboia, Bun gar us fasc. et ccerul., and Echts biting each other . . . 17 Analytic summary of results ............ 19 PART IV. Effect of Venom on Innocent Snakes. Own experiments with Cobra-venom . . . . . . . . . . .19 Details ............... 20 Results ....... ........21 Experiments of previous observers ........... 21 Details ............... 22 General summary of results ............ 23 PART V. Effect of Venom on other Cold-blooded Animals— Vertebrate and Invertebrate. On Alligator 23 „ Lizard 23 „ Tortoise and Turtle ............. 23 „ Frog 23 „ „ , further experiments 24 „ Fish 25 „ Invertebrates 25 PART VI. What is the cause of the Serpents' immunity from their Venom ? Immunity not secured through being cold-blooded 25 Ditto ditto anatomical or physiological peculiarity of ophidian form . . 25 Ditto ditto mere possession of a poison-apparatus 26 Hypothesis offered to explain immunity 26 Additional arguments favoring hypothesis .......... 27 Injection of purely chemical material alleged to procure immunity from specific disease . 27 Venom not a general protoplasm-poison . . . . . . . . . 27 Habituation of protoplasm to foreign food 27 Fancied inoculation among Snake-charmers ......... 27 Inter-immunity of Venomous Snakes explainable . ....... 28 Conclusion . 28 Are Venomous Snakes auto-toxic? An Inquiry into the Effect of Serpent-Venom upon the Serpents themselves. Surgeon L. A. WADDELL, m.b., DEPUTY SANITARY COMMISSIONER, BENGAL. Seeming anomaly of subject. INTRODUCTORY. An interesting question which presents itself in studying the phenomena of serpent-poisoning is that which refers to the insus- Practical bearing of inquiry. ,i • r , , ceptibility or otherwise ot a serpent to its own venom, or that of its fellows. And this question is not without a practical bearing upon the treatment of snake-bite : for, were such immunity proved to exist, a study of its conditions might possibly afford indications for combating the action of the venom on man. That an animal should be subject to poisoning by one of its own normal secretions, must ,primd facie , seem improbable, as this would prove detrimental to the individual and to the species. And especially so, when, as in the present case, the exposure to poison- ing would be habitual : for snakes are frequently receiving accidental injuries to the mouth, with abrasion of the mucous membrane of the buccal cavity, and thus, not unfrequently, must absorb some of their own venom.1 Should, on the contrary, snakes be proof against poisoning by their own venom, then the problem presents itself of how to account for the organism of the serpent being able to resist a chemical poison which is so deadly to most other animals. As to whether such insusceptibility really exists, authorities differ widely in Conflict of opinion on question. opinion. On the one hand are those who assert the existence of this insuscep- tibility ; — Fontana, in 1765, experimenting on the European Viper {Viper aspis ?) con- Favouring view of insuscepti- eluded that" the venom of the viper is neither a blllty- poison to the viper itself, nor to those of its own species.”2 1 This fact was pointed out long ago by Fontana in regard to the Viper (‘ Treatise on the Venom of the Viper, &c.,’ Skinner’s transl. London, 1795, Vol. I, p. 274). 2 loc. cit. p. 34. His experiments on this head, over twenty in number, were admirably conceived and carried out. 4 Scientific Memoirs by Russell,1 Fayrer,2 Richards,3 Nicholson,4 and Hopley 6 give results of experi- ments or observations which led them to conclude that the cobra ( Naja tripu- dians ) is insensible to its own venom or to that of its fellow species. And Indian snake-charmers also hav'e come, by experience or tradition, to hold the same belief. Breton 8 and Fayrer 7 extended to poisonous snakes in general this principle of insusceptibility. And analogous experiments upon scorpions, by Bourne 8 and others 9 led to the conclusion that the poison of a scorpion is quite powerless to kill the same individual, or another individual of the same, or even of another species. On the other hand, Professor Weir Mitchell of Philadelphia — whose very elaborate researches entitle him to the first rank as In favour of susceptibility. . . . . an authority on snake-venom — states that he felt “ at liberty to conclude that the animals ( crotali ) . . really died from the venom ( crotalus ).” And11 that the venom of the rattlesnake is “ poisonous . . to its owner” “as well as to other animals.” Mitchell’s experiments in this direction were confined to rattlesnakes, but it is unlikely that the principle involved should differ materially in the case of the rattlesnake from that of the cobra and other venomous snakes. Popular reports also credit venomous snakes occasion- ally with biting themselves with rapidly fatal results.12 As intermediate between these antagonistic views may be cited the ap- Mixed views parently contradictory opinions of Fayrer and of Richards. Although Fayrer, in summarizing his con- 1 “ An Account of Indian Serpents'’ Lond. 1796, p. 56. He made one cobra bite another, with the result that the bitten cobra “ remained well.” “ This experiment was repeated with the like result.” This cobra some days afterwards was bitten in the belly by another cobra, “blood appeared on the wound but no other consequence followed.” While an innocent snake, “ a tartutta ( Dipsas trigonata ?), bitten immediately after in the same, part, died within two hours.” 2 “ The Thanatophidia of India,” Lond. 1872, p. 66 et. seq. 3 Idem, p. 125 et seq. 4 “Indian Snakes,” 2nd Ed., Madras, 1874, p. 145. 5 “ Snakes'. Curiosities and Wonders of Serpent Life.” Lond. 1882, p. 563. 6 Trans. Med. and Phys. Soc. Calcutta, 1826, Vol. I, p. 170. This conclusion, however, was based upon one solitary experiment on a cobra and a Daboia russellii biting each other. 7 loc. cit. p. 64, “ The poisonous snakes are not affected by their own poison.” In support of this state- ment is given, in addition to the experiments on cobras, one case of a £ krait ’ ( Bungarus cceruleus) bitten by another krait with “ no effect ” (p. 134; ; and Richards reports (p. 127, idem) another case in which the small bitten krait was “found dead” the following morning. But no further experiments seem to have been made upon kraits, and none upon any of the other species of venomous snakes of India. Re- garding the effect of venom upon another venomous snake, Fayrer states (p. 73) that the experiment recorded seems to prove that the venomous snakes have no power of poisoning each other,” and (at p. 64) “ in many of the various experiments I have performed, the Cobra, Daboia and Krait did not appear able to poison themselves or each other.” 8 Proc. Roy . Soc., p. 20 xlii, 1887. He experimented on three species of scorpions found in Madras, with the view of determining whether scorpions can commit suicide. 9 Ray Lankester and others, from experiments made at Cape Town, about six years ago, arrived, 1 am informed, at somewhat similar conclusions ; but I can find no published record of their results. 10 “ Researches on the Physiology and Toxicology of the Venom of the Rattlesnake.” (Vol. XII, Smithson. Contrib.) Washington, i860, p. 63. 11 Idem, p. 43. 12 Nature, Vol. XXII, p. 40. And Fontana and Mitchell refer to the currency of this belief. 5 Medical Officers of the Army of India. elusions states at one place definitely and unreservedly,1 that “ the poisonous snakes are not affected by theif own poison,” yet, he notes on the following page that, although “ in many of the various experiments I have performed, the Cobra, Daboia, and Krait did not appear able to poison themselves or each other, some of the experiments render this doubtful." And Richards, although noting2 that “ I believe one cobra cannot poison another” and3 “I am quite satisfied the cobra cannot kill another cobra;” and recently4 he relates how healthy cobras, which he kept together in captivity, would ‘‘very often on the slightest provocation begin to fight in a most savage” fashion, biting each other fiercely, with the result that “neither of the combat- ants ever seemed any the worse for the fight.” Yet, he notes,6 “ I came to the conclusion, after numerous experiments, that one species of snake could kill another” (by the context) venomous snake of the same species.6 Such conflict of opinion upon so elementary a point rendered a further Desirability of further investiga- investigation of the subject desirable— especially, tion. as the methods adopted by several of the foregoing experimenters, to elucidate the point at issue, were open to objection. Part I.— Working Scheme adopted. The inquiry resolves itself into a consideration of the effect of venom , (1)upon the serpent itself and its own species, (2)upon Scope of inquiry defined. 1 ,,, . venomous snakes of other species, wupon innocent snakes, (4)upon other reptiles and cold-blooded animals, (B)upon warm-blooded animals ; and of the topics arising out of the results of the above investigations. It is claimed for the present series of experiments that they have avoided , many of the sources of experimental error to which Sources of experimental error. , J ' . r those ot former observers were liable : — The method .usually employed to ascertain the toxic effect of snake-venom injury to viscera, &c., during upon snakes had been to force one snake to bite infliction or bite. another, or its own tail. In this way, however, there is always a probability that the spine or viscera of the bitten snake were crushed, or otherwise grossly injured during the act of biting.7 Again, in erUploying biting as a means of introducing venom, there is un- Un certain introduction of venom certainty as to the amount of venom introduced; by biting. and jn some cases uncertainty as to whether any venom at all has been injected — owing to the want of anatomical continuity 1 loc. cit., p. 64. 3 idem, p. 126. 3 idem, p.127. 4 Landmarks of Snake-poison Literature. 2nd Ed. Calcutta, 1886, p. 12. 0 idem, p. 12. 6 No details of the experiments are given. 7 In Fayrer’s series of cobras-bitten-by-cbbras no post-mortem examination appears to have been made to ascertain whether any such fatal injury had been inflicted. B 6 Scientific Memoirs by between the venom-duct and the canal of the fang and the more or less erectile nature of the fang — especially in vipers.1 The “ difficulty in making the viper ( Daboia ) insert its long slender fangs into the tough skin of the cobra ” is noted.2 The venom may in part be washed out with the blood escaping from the wounded part.3 The snake may have recently shed its venom and have little more available.4 * Snakes are also credited with being able to control the flow of their venom, expelling a larger quantity when irritated and rendered furious than in ordinary biting.6 A generally recognised difficulty in interpreting the results of such experi- „ ments is the frequent mortality of captive snakes. Mortality of captive snakes. _ A. - * _ . In Fayrer s experiments the majority of the snakes operated upon may have been fresh, but the fact is only notd’d in regard to one of the bitten snakes. Mitchell’s experiments appear to have been made upon snakes which had been in confinement for a considerable time. 8 The necessity for prolonged observation of the envenomed snake is Necessity for prolonged observ- strongly insisted upon by Mitchell 7 and Claude atl0n- Bernard 8 on the plea that cold-blooded animals are very much less rapidly affected by venom than the warm-blooded, and hence the necessity, in their opinion, for the snake being kept under observation during a period of several consecutive days.9 It is also desirable that the venom experimented with be of ascertained Using venom of unascertained activity. This precaution had been very seldom activity. observed. In the present series of experiments the above-noted sources of error were _ , to a considerable extent avoided or minimized by General precautions taken. ... . J the employment of freshly-caught uninjured snakes, by introducing without loss a measured quantity of the venom by the more precise mode of hypodermic injection,10 by prolonged observation, and by resort- ing to numerous control experiments to test the activity of the'venom. 1 Dr. Mitchell notes ( loc . cit., p. 25)," I have seen the Rattlesnake strike with great apparent ferocity a number of times, when I have been unable to discover any fang wound whatsoever.” Again, “ in some cases it is quite possible that the relations of the fang and the duct are so disturbed that the venom never enters the tooth at all.” And “ It sometimes happens that the blow is given, the fang enters, and from the quick starting of the animal injured, or from some other interrupting cause, it is withdrawn so soon that the larger portion of the poison is thrown harmless upon the surface near the wound.” 2 Fayrer, loc. cit., p. 92. 3 ■ Fontana, loc. cit., p. 139. 4 idem, p. 140. 5 idem, p. 139. 6 loc. cit., p. 61. 7 loc. cit., p. 63. 8 “Lemons sur les Effets des Substances Toxiques, etc.” 1857, p. 291 — quoted by Mitchell, who affords a very full bibliography of serpent-venom literature. 9 In a fourth of Fayrer’s experiments the observations were continued for only one day, and in another fourth for two days only. 10 Fayrer, loc. cit., p. 75 et seq., records seven cases in which cobra-venom was introduced hypoder- mically into cobras, but in only two was the observation extended till the sixth day, and in none beyond th sixth day, and no control observations were made. Medical Officers of the Army of India. 7 Part II. — Effect of Venom upon the Serpent itself, or its own Species. The experiments under this head were confined to the cobra ( Naja tripu- The Experiments dians), as, with the exception of tree-vipers, other species of venomous snakes were not available. And the experiments, with one exception, dealt with the strictly auto-toxic aspect of the subject. Concerning the ability of one venomous snake to poison another individual of the same species, the one experiment (No, XX) here afforded seems almost sufficient when taken in connexion with the numerous experiments recorded by Fayrer 1 and others,2 in which one cobra was forced to bite another cobra. Moreover, snake-venom ( e.g ., cobra or crotalus venom), from whatever individual derived, is found to possess for each species such constant and well defined properties, that it may well be regarded as a specific chemical poison ; 3 and as such it is highly probable that the venom shall act upon another snake of the same species in an identical manner to its action upon the owner of the venom. The number of cobras operated on was nine, in three series of four, four, and one respectively. I had hoped to operate on a larger General arrangements. , number, but failed to procure more by my unaided private efforts within the limited time at my disposal. The first series of experiments was conducted at the end of August of the current year, the temperature of the room in which the snakes were kept, ran- ging from 8i° to 86° Fah. The second series was conducted at the beginning of October, the temperature ranging between 65° and 88° Fah. And the third series at the beginning of November, the temperature ranging between 540 and 78° Fah. The serpents operated on were all healthy, and had been caught within the previous two to seven days. In the experiments the venom was extracted in the usual Indian way by causing each cobra to bite through a strip of dried palm leaf i stretched across a spoon or valve of a mussel-shell. For injecting the venom an ordinary hypoder- mic syringe was used. And during the process of injection the serpent was secured by a noose around the neck after the manner recommended by Mitchell. Details of the Experiments. First Series of Cobras. Experiment I. — A binocellated cobra {^Gokhura ’), measuring 53 inches in length, was made to disgorge its venom. About 18 minims of clear venom were 1 The results of these scattered experiments are collected and analyzed at p. 13 (q. ©.). 2 Russell and Richards, loc. tit. 3 For evidence on this head vide Part VI. 4 Borassus flabelliformis. C 8 Scientific Memoirs by obtained. This venom was mixed with an equal bulk of water, and at 9-15 A.M., 25 minims of this solution were injected hypodermically (and very slightly supra- muscularly) about the middle of the back of this cobra — the same which had yielded the venom. Atmospheric temperature 82° Fah. This snake was observed every hour during the day and seemed unaffected. Next day.— -Active and well. Fierce when disturbed. 3rd >. Ditto. * 4th ,, Ditto. 5th «. Ditto. Taken out of its cage it bit eagerly, yielding about 9 minims of clear venom. 6th „ Ditto. 7 th ,, Ditto. 8th „ Ditto. 9th „ Ditto. Taken out of its cage it bit vigorously, yielding about 4 minims of slightly cloudy venom. It was immediately thereafter killed and dissected. Post-mortem Examination. — Wound healed, and at site of injection no stain- ing or softening of tissues. All organs strictly normal in appearance. To test the activity of the venom employed in Experiment I the following two experiments were made immediately after injecting the cobra : — Experiment II. — The remainder of the same venom solution as was used in Experiment I was diluted with an equal volume of water, and of this solution 6 minims were injected hypodermically into inner side of thigh of a chicken weighing 14^ ounces. Atmospheric temperature 82° Fah. 9-19 A.M. — Time of injection. 9-22 „ — Unable to stand, beak resting on ground. 9-23 ,, — Convulsions ; passing faeces. 9-30 ,, — Almost dead. 9-33 —Dead. Experiment III. — Nine minims of same solution as used in last Experiment (II) were injected hypodermically into thigh of chicken weighing 15 ozs. At- mospheric temperature 82° Fah. 9-24 A.M. — Time of injection. 9-28 ,, — Drooping. 9-30 ,, — Convulsions. 9*35 j) — Almost dead. 9-41 ,, — Dead. Experiment IV. — A very fierce monocellated cobra (‘ Shankha mutiya Ki-otia ’) measuring 53! inches in length, was made to disgorge its venom — yielding about 20 minims. This venom was diluted with an equal bulk of water, and at 10-5 A.M., 25 minims were injected hypodermically about middle of back of this same cobra which had yielded the venom. 9 Medical Officers of the Army of India. This snake was observed every hour during the day and seemed to be unaffected. Next day. — Active and well. Very fierce when disturbed. 3rd to gth day. — Active and well.. Very fierce when disturbed. It was taken out of its cage on the fifth and ninth days and bit eagerly, yield- ing clear venom. On the ninth day it was killed and dissected. Post-mortem Examination. — The skin over site of injection slightly dry and wrinkled, but no subjacent exudation or softening of tissues — only a faint capil- lary staining subcutaneously at seat of injection. Organs strictly normal in appearance. To test the activity of the venom used in Experimeht IV the following two experiments were made : — Experiment V. — Of the remainder of the solution used in Experiment IV, 8 minims were injected subcutaneously into thigh of a chicken weighing 14 ozs- 10-18 A.M. — Time of injection. 10-20 ,, — Prostrate ; beak resting on ground. 10-25 ,, — Convulsions. 10-28 „ — Dead. Experiment VI. — Of same solution as used in last experiment 4 minims were injected into thigh of a chicken weighing 10 ozs. — io-2i A. M.— Time of injection. 10-28 „ — Convulsions. 10-32 ,, — Dead. EXPERIMENT VII. — A monocellated cobra (‘ Adyat ki-otia ’), measuring 43 inches in length, yielded about 12 minims of venom. This was diluted with an equal volume of water, and at 10-45 A-M*> 12 minims were injected hypodermi- cally into this same cobra, as in Experiments I and IV. During the day no effect was observable, and the snake remained well and active up till the ninth day, when it was killed and dissected. Post-mortem Examination. — Wound healed, no softening of tissues or exu- dation, very slight capillary staining limited to track of syringe-needle. Organs strictly normal. To test the activity of the venom used in Experiment VII the following two experiments were made : — Experiment VIII. — Of the remainder of the solution used in last experi- ment No. VII, 8 minims were injected subcutaneously into thigh of a chicken weighing 14 ozs. — 10- 51 A.M.—' Time of injection. 11- 10 „ —Convulsions. 11-23 » —Dead. D IO Scientific Memoirs by Experiment IX. — Of the same solution as was used in last experiment 4 minims were similarly injected into a chicken weighing 13 ozs. — 10- 53 A>M> — Time of injection. 1 1 - 1 1 „ — Convulsions. 11- 30 ,, — Dead. EXPERIMENT X. — A small binocellated cobra (‘ Kala Gokhura ’), measuring 34 inches in length, yielded about 10 minims of venom. This was mixed with double its bulk of water, and 15 minims of this solution injected into this same cobra. The injection appeared to be without effect. The snake was observed several times during that day and following days, and found at all times to be actively on the alert. On the fifth and ninth days following injection, it bit eagerly, yielding clear venom. On the ninth day it was killed and dissected. Post-mortem Examination. — Wound healed, no exudation, softening, of staining of the tissues at seat of injection. Organs strictly normal. To test the activity of the venom used in Experiment X, the following two experiments were made immediately thereafter : — Experiment XI. — Of the remainder of the solution used in Experiment X, 8 minims were hypodermically injected into a chicken weighing 14 ozs. — 11-28 A.M. — Time of injection into thigh of chicken. n-37 » — Convulsions. 11-42 „ — Dead. Experiment XII. — Of the same Solution as was used in last experiment 4 minims were similarly injected into a chicken weighing 10 ozs. — 1 1-30 A.M. — Injection into chicken’s thigh. 11-36 ,) — Convulsions. 11-43 ,, — Dead. Second Series of Cobras. Experiment XIII. — A very large binocellated cobra, measuring 59A inches in length, yielded about 9 minims of straw-coloured clear venom. This was mixed with an equal quantity of water, and of this solution 15 minims were injected hypodermically about middle of back. During that day the snake appeared unaffected, and no change was noted during the subsequent fourteen days. On the fifteenth day after injection, the snake was active and furious, it bit vigorously, yielding a small amount of clear venom — the greater portion escaping into snake’s mouth. It was immediately thereafter killed and dissected. Temperature during its captivity ranged between 65° and 78° Fah. Post-mortem Examination. — No morbid appearances externally over site of injection. Subcutaneously slight limited swelling about size of small split-pea Medical Officers of the Army of India. 1 1 beneath fascia, which had been pricked by injection needle, but no softening or exudation. Viscera strictly normal in appearance. To test the activity of the venom used in Experiment XIII, the following experiment was made : — Experiment XIV. — The remaining 3 minims of the solution used in ex- periment XIII were injected hypodermically into inner aspect of right thigh of a chicken weighing 15 ozs. — 11- 9 A.M. — Time of injection. 1 1 - 1 7 „ — Head drooping. 11-20 ,, — Lying on side paralysed. 11-22 ,, — Convulsions. n-33 „ — Nearly dead. 1 1-35 » —Dead. Experiment XV. — A large binocellated cobra (‘ Kdla Gokhura') , measuring 47f inches in length, yielded about 12 minims of light straw-colored clear venom. This was mixed with an equal bulk of water, and of this solution 20 minims were injected hypodermically about middle of back of this same snake. Temperature as in Experiment XIII. During that day no change was apparent. Nor was any change evident up to the fifteenth day after injection, when the snake was taken out of its cage, and it bit fiercely, yielding clear venom. It was immediately thereafter killed and dissected. Post-mortem Examination. — Slight wrinkling and dulness of skin over site of injection. No exudation or staining or softening subcutaneously; but point of needle had pricked the sheath of the spinal muscles, and sub-fascially around site of puncture was a small inflammatory nodule about size of a small pea, red on section, and of cheesy consistence. Viscera strictly normal in appearance. To test the activity of the venom used in Experiment XV, the following experiment was made : — Experiment XVI. — The remaining 4 minims of the solution used in Ex- periment XV were injected hypodermically into thigh of a fowl weighing 24 ozs. — 11-39 A.M. — Time of injection. 11-46 A.M. — Beak resting on ground. 1 1-53 A.M. — Lying on side with convulsive gaspings. 1 1-59 A.M. — Dead. Experiment XVII. — A vigorous monocellated cobra (‘ Shankha mutiya Ki-otia ’), measuring /\6\ inches in length, yielded about 15 minims of clear color- less venom. This was mixed with an equal bulk of water, and 25 minims of this solution were injected hypodermically about middle of back of this cobra. E 12 Scientific Memoirs by Temperature as in Experiment XIII. During that day it seemed unaffected. Nor did it seem affected during the fourteen subsequent days. On the fifteenth day after injection it was taken out of its cage and it bit fiercely, yielding clear venom. It was immediately thereafter killed and dissected. Post-mortem Examination.-^-No local signs whatsoever. Organs strictly normal in appearance. To test the activity of the venom used in Experiment XVII, the following experiment was made : — Experiment XVIII. — The remaining 5 minims of the same solution used in Experiment XVII were injected hypodermically into the thigh of a fowl weighing 30 ozs. — 12 noon. — Time of injection. 12-4 P.M. — Sitting with beak resting on ground. 12-20 „ — Convulsions. 12-23 ,, t — Dead. Experiment XIX. — A large binocellated cobra, measuring 5 if inches in length, had 7 grains of cobra venom (obtained from another cobra one month previously and of ascertained activity1) dissolved in 15 minims of water injected hypodermically about middle of back. Temperature as in Experiment XIII. During that day it seemed to remain unaffected, and so it also remained during the following fourteen days. On the fifteenth day following the injection, the snake was taken out of its cage, and bit vigorously, yielding clear venom. It was immediately thereafter killed and dissected. Post-mortem Examination. — No local signs evident. Viscera generally were slightly congested, but not otherwise abnormal in appearance, and no fluid extravasation had occurred into any of the cavities. Third Series of Cobras. EXPERIMENT XX. — A large active binocellated cobra, measuring 58 inches in length, yielded about 16 minims of clear venom. This was diluted with an equal bulk of water, and of this solution 28 minims were injected hypodermically about middle of back of this same cobra. Temperature 70° Fah. During the day it seemed to remain unaffected, nor did it appear affect- ed during the subsequent fifteen days. On the fifteenth day it was killed and dissected. Post-mortem Examination. — Skin slightly dry and wrinkled over seat of in- jection, very faint localized staining subcutaneously at point where needle pene- trated cuticle, The subjacent muscle here to extent of about size of split-pea semi- diffluent, but free from purulent products. Viscera strictly normal in appearance. 1 One and a half grains dissolved in water killed in 20 minutes a chicken weighing 16 ozs. Medical Officers of the Army of India. *3 To test the activity of the venom used in Experiment XX the following experiment was made immediately after injecting the cobra : — Experiment XXI. — Two minims of the same solution as was used in Experiment XX were hypodermically injected into thigh of a fowl weighing 31 ozs.— 8-25 A.M. — Time of injection. 8- 50 „ — Drooping in sitting position. 9- 5 ,, — Beak resting on ground. 9-1^ ,, — Lying on side. 9-50 ,, — Dead. The results of these experiments unequivocally demonstrate that the cobra is practically, if not wholly, insusceptible to the Results of these experiments. . ~ toxic action of its own venom. In the first series, the cobras were kept under observation for nine days, in the second series for fifteen days, and in the third for fifteen days. And the fact that each series of experiments was conducted under different conditions as to locality,1 elevation above sea-level, temperature, and season, tended to eliminate local sources of experimental error. In view of the absolute uniformity of results which has obtained throughout Review of Mitchell and Fayrer’s these experiments, it becomes desirable to review anomalous experiments. the details of those experiments by Mitchell and Fayrer which seem to have been attended by exceptional or anomalous results, in order to ascertain whether the seemingly anomalous results may not be attribut- able to accident. The experiments recorded by Fayrer upon cobra-venom versus the cobra Fayrer’s experiments on cobras are 23 m number, VIZ. 1 6 on Cobras bitten by CO” versus cobras. bras and 7 in which cobra-venom was injected hypo- dermically into cobras. In these 23 experiments there were only three deaths. Reviewing the particulars of these three fatal cases it is to be remarked in regard to the first case,2 that no post-mortem examination was made to ascertain whether the needle had not entered a blood-vessel or viscus, or the non-existence of any other obvious cause of death. Neither is it stated whether the snake was a fresh or vigorous one. In six further experiments of a similar nature the cobras are reported to have survived. In regard to the second fatal case3 — a young cobra “ 10 inches long” and “ only 10 or 14 days old ” — the marvel is that it survived so long (six days) in captivity after having been wrounded by biting. In the third case4 the cobra was reported next day “ perfectly well,” and it seems to have lived for six days. The death may have been due to starvation, 1 Two of the places were about 200 miles apart. 2 loc. cit., p. 75. 3 loc, cit., p. 99. 4 idem, p. 120. F Scientific Memoirs by septicaemia, or other accidental causes. No post-mortem examination appears to have been made. Thus, in regard to neither of these three cases is there evidence to show that the fatal event was due to the venom. On the contrary, the likelihood that death resulted from other and accidental causes is so great that these three experiments may well be eliminated from the series ; and when so eliminated, there remain 20 experiments, with no deaths. Mitchell records1 seven experiments on rattlesnakes with rattlesnake Mitchell’s experiments on rattle- venom, and concludes that “ the above experiments snakes versus rattlesnakes. were on the whole so definite in their results that I did not think it necessary to multiply them,” and that these rattlesnakes “really died from the venom.” An examination, however, of the details of his experiments renders it difficult to conceive how Dr. Mitchell was led to such a conclusion. But before examining the particulars of these experiments seriatim, it is necessary to remember, firstly, that these snakes had been for some time in captivity — the record of these experiments being prefaced by the remark “ at the close of a series of experiments on warm-blooded (animals) I made use of some of my largest snakes in the following manner.” 1 And, secondly, that these snakes appear to have been repeatedly subjected to extremely rough handling and forcible compression of the poison-glands during extraction of the venom — a process so severe that it is noted, 2 “ One snake in every four died within two to five days” from the mere effects of the process for extracting their venom. And to this process the snakes of Experiments I, III, V, VI and VII, seem to have been subjected during their final experiment. In Experiment I, the snake did not die till the fourteenth day after being bitten, and it presented no signs of viper-poisoning. 3 In Experiment II, the snake “died on the fourteenth day. The wound was apparently healthy.”. . . “The blood was uncoagulated, but there was no other visible lesion of any internal organ.” Concerning Experiment III, it is noted, “ In all probability this serpent died from some other cause than venom-poisoning.” In Experiment IV the snake “ recovered,” although it bit itself three times on a part from which skin had been removed, throwing out “a good deal of venom which was thrust deeply into the muscles of wounded part.” “ No blood was effused ” and “at the close of two weeks this snake was healthy and bit eagerly.” In Experiment V, although the snake lived for 36 hours after injection of poison, there appears to have been no extravasation of blood, except that the stomach “ contained bloody mucus.” The wound “was not stained with blood.” “The heart was full of clotted blood.” In Experiment VI, where the snake lived for about three days, it is recorded that the local appearances were even “ less extensive ” than in last 1 loc. cit., p. 61 et seq. 2 idem, p. 29, the author remarking that “it is not impossible that too severe a compression of the venom -gland may produce rupture of its substance and consequent blood-poisoning.” 3 Fluidity of blood with bloody extravasations are the leading physical signs of viper-poisoning. Medical Officers oj the Army of India. *5 experiment. “ The interior organs were healthy, and the heart contained loose soft clots.” In Experiment VII, the snake died on the seventh day and had bloody extravasations into the peritoneal cavity, and the intestines were spotted with ecchymoses. But such appearances are common to death from septicaemia, and it is noted that the wound “ penetrated the muscles, which were dark and much softened.” Thus, taking this series of Dr. Mitchell’s observations as a whole, and Mitchell’s inference from his ex- keeping in view the above -noted sources of error to periment scarcely warranted. which these experiments were especially subject, we find that the results, far from “ definitely ” warranting the conclusion that the rattlesnakes “really died from the venom,” can more readily be interpreted as supporting quite an opposite conclusion. And this opposite conclusion gains from Dr. Mitchell further support from his observation1 that in the “ numerous instances in which I had wounded the mouths of rattlesnakes or torn the vagina dentis while robbing them of poison, on none of these occasions have any serious resuhs followed the injury, even where the venom had fallen upon the abraded surfaces in considerable amount.” Summarizing the results of all the foregoing observations, it will be seen General conclusion on the auto- that, when the suspicious elements are eliminated toxicity of venom. from the experiments of Mitchell2 and of Fayrer, the results are in accordance with those of the present series of experiments, and also with the recorded rough experiments of Russell and of Richards upon cobras biting each other; and, that they generally confirm and extend the prin- ciple formulated by Fontana in regard to viper-venom, viz. “that the venom . . . is neither a poison to the snake itself nor to those of its own species.”3 In inquiring into the cause of venomous snakes (all ?) being immune to their own venom or that of their species, it becomes necessary to ascertain the effect of venom upon snakes of other species — venomous and non-venomous, as well as upon other cold-blooded animals. As to warm-blooded animals, all modern observers seem agreed in confirming the conclusion arrived at by Fontana from experiment on all the available warm-blooded animals in Italy, viz., that venom “ is a poison to all warm-blooded animals.” 4 Part III. — Effect of Venom on Venomous Snakes of other Species. For experiment under this head, only pit-vipers, three in number, were avail- able ; my endeavours to procure other kinds of venomous snakes so late in the season having proved unsuccessful. 1 loc. cit., p. 63. 2 Further experiments on rattlesnakes are desirable in order to remove all ambiguity. 3 loc. c'it., p. 34. 4 loc. cit. p. 273. Certain American writers consider the pig immune to venom ( New York Med. Jour., p. 54, 1884), but more authentic evidence on this point is needed. G 1 6 Scientific Memoirs by Upon these three vipers the effect of cobra-venom was tried. The details Effect of cobra-venom on Tri- of the experiments are as follow : — meresuri. Experiment No. XXII. — A newly caught vigorous large Trimeresurus erythrurus, measuring 29^ inches in length, had, at 8-15 A M., 4 grains of fresh dry cobra-venom of ascertained activity dissolved in 12 minims of water, and injected hypodermically about middle of back. Atmospheric temperature 82° Fah. — 8-15 A.M. — Time of injection. 8-18 ,, — Actively crawling up sides of cage. 8- 30 ,, — Still active. 9 ,, — Very quiet. 9- 15 „ —Dead. Post-mortem dissection. — Heart continued pulsating till 1-5 p.m. The injection had been strictly hypodermic. Muscles not wounded, and only a faint streak of capillary haemorrhage at seat of injection. Viscera normal in appearance. Experiment No. XXIII. — A newly caught very active small Trimeresur- us erythrurus , measuring I2f inches, had injected hypodermically about middle of back 8 minims of same solution of cobra-venom, of which 5 minims had killed a chicken weighing ifb in 20 minutes. Atmospheric temperature 85° Fah. — 1 1 - 1 7 A.M. — Injection. 1 1 - 1 9 „ — Actively moving. 1 1-25 ,, — Scarcely able to move. 11-29 >> — When turned over on back, unable to regain position. 11-36 ,, — Exhibits no movement unless pinched, and then only faintly moves the tail and neck. 11-42 „ — Dead. Post-mortem dissection showed the injection to have been purely hypoder- mic. The snake had been captured only a few minutes before, and was un- injured during capture, and during injection was not roughly handled. Experiment No. XXIV. — A freshly caught active Trimeresurus gra- mineus, measuring 27 inches long, had, at 8-45 A.M., 7 minims of fresh cobra- venom, diluted with an equal bulk of water, injected hypodermically about middle of back. Atmospheric temperature 82° Fah. — 8- 45 A.M. — Injection. 8 50 ,, — Actively moving. 9- 15 „ — Scarcely able to move. 9-25 ,, — Almost dead. 9-32 „ —Dead. Post-mortem dissection showed that the injection had been very slightly intra-muscular as well as subcutaneous. Only faint streak capillary haemorrh- age locally. Viscera normal in appearance. Medical Officers of the Army of India, *7 I here present a summary of all the published observations I can find, Effect Of Cobra, Daboia, Bunga- relating to the toxic action of venomous snakes upon Yus and Echis biting each other. each 0ther. The snakes comprise the Cobra, Daboia, Bungarus fasciatus et cceruleus , and Echis carinata. And the toxic effect was estimated by forcing one snake to bite another of a different species — Page of Nature of Observation. Serial No. of Case. Observer. ‘ Thana- :ophidin of India ’ where re- Time under observation after bite. Result. Remarks. ported. Cobra biting Daboia rus- j Breton 1 2 days “ No effect.” sellii. 2 Fayrer 73 5 » „ „ 3 80 6 „ “ Remained 4 85 Not stated . well.” 5 „ 85 „ » „ » 6 92 „ „ ,, ,, 7 98 2\ days “No change.” 8 ” IOI 7 » ” Cobra biting Bungarus ! Fayrer 74 29 hours . Died Had been twice bitten by a fasciatus. large cobra. 2 ” 85 4 days » “ Lung and thorax filled with blood,” indicating visceral or vascular lesion. 3 92 i8f hours . u Been bitten three times. 4 ” 100 5 days . “Well and active.” Died thirteen days after bite. 5 " 107 1 day Died “ Appears to have received some injury about head and neck.” 6 108 2\ hours ,, Bitten twice ‘ near tail.’ 7 » 1x9 5 days . Day following bite “perfectly well.” When died “wound had become putrid.” Cobra biting Echis carin- ! Fayrer 140 20 hours . Died. ata. 2 « ” 1 day ” Cobra biting Bungarus cceruleus . 1 Fayrer 124 ;o minutes Died “The fangs of the cobra were heard to strike the krait’s 2 Richards 125 1 day “ Found . spine.” It is noted, “ Death cannot be dead.” attributed to rough hand- ling.” 3 f> 127 1 hour Died The krait ( Bungarus ) was only 1 foot 10 inches long, and the cobra was full grown. 4 127 if days . “ Quite well” Krait was feet long. 5 „ 142 Q “No result ” Daboia russellii biting j Russell2 Not stated . “No symp- Cobra. 2 Breton 1 6 days toms.” Not affected. 3 Fayrer '80 “No effect.” 4 83 1 day “No change.” The cobra was ‘full grown.’ 5 44 hours . Died Ho post-mortem examination seems to have been made. 1 loc. cit., p. 175. | 2 loc. cit., p. 85. 1 8 Scientific Memoirs by Page of ‘ Thana- tophidin of India ’ where re- Nature of Observation. Serial No. of Case. Observer. Time under observation after bite. Result. Remarks. ported. Daboia russellii biting 6 Fayrer 83 i| days Little, if any Cobra — contd. effect. 7 „ 9f ,1 1 a jj “No effect.” 8 „ 85 2 „ Little, if any effect. 9 ,, 92 5 » “Quite well.” io 99 4 » Died Cobra was only “ 10 or 14 days old.” ii 101 7 » “Nochange.” 12 Richards 127 1 day Died Death “possibly from injury done by the viper’s enormous fangs.” But no post-mortem examination seems to have been made. Daboia biting Bungarus F ayrer 100 13 days . “ Remained fasciatus. unaffected.” Daboia biting Bungarus I Fayrer 140 Not stated . “Unaffected” cceruleus. Bungarus fasciatus biting I Fayrer | 69 1 day “Well.” Cobra. Bungarus cceruleus biting Cobra. I Fayrer 120 2 days “ Found dead.” Morning following bite was “ unaffected.” 2 133 7 » “Not, nor has been, affected.” 3 134 32 minutes . Died Cobra was only 14 inches long. and krait was 48 inches. 4 99 140 4 days “Quite well.” 5 Richards 125 3 “ Well.” . 6 99 127 1 day Died Cobra was of “small size.” 7 142 2 days It is noted, “The death may not be due to the bite, as many of the snakes are dying at present.” Bungarus cceruleus biting i Fayrer 138 Not stated . “ Not affect- Echis. ed.” Echis carinata biting i Fayrer 136 i| days . Died During day of bite “no effect Cobra. apparent.” Echis biting Bungarus Fayrer 136 2 days . “Quite well.” cceruleus. 2 » 138 Not stated . “ Not affect- ed.” 3 ” 140 4 days “ No effect.” Medical Officers of the Army of India, *9 Analytic summary of results. In analyzing the experiments shown in the table, it is to be remembered that they were subject to most of the experimental errors already referred to in Part I, so that many of the experiments must be eliminated. When the series is thus modified many of the divergent results disappear ; but much uncertainty must remain until more exact experiments are forthcoming. At present the nett result of these experi- ments may be stated as showing that — - (1) the Cobra-bite is inoperative on Daboia russellii, doubtfully operative on Bungarus fasciatus and Bungarus c&ruleus , and fatal to Echis carinata ; (2) the Daboia- bite is inoperative on the Cobra and Bungarus fasciatus and Bungarus caeruleus ; but the experiments with Bungarus being solitary ones and merely by biting are inconclusive; (3) the Bungarus caeruleus-Wte is inoperative on the Cobra and doubtfully so on Echis; (4) the Bungarus fasciatus- bite is apparently inoperative on the Cobra ; (5) the Echis- bite is inoperative on Bungarus cseruleus. My experiments showed that Cobra-venom is rapidly fatal to two species of the green tree- viper ( Trimeresurus ). Part IV. — Effect of Venom on Innocent Snakes. The results of my experiments upon the effect of venom on innocent snakes — 16 in. number — are shown in the following ve°” e’‘i’erimen,s '»ith “bra- table. It is to be noted that all the snakes operat- ed on had been newly caught, and, except where otherwise stated, vigorous and uninjured ; the solution of venom was freshly made and subcutaneously injected about middle of back, and the activity of the venom solution had in every case been ascertained by control experiments on fowls. The snakes nearly always passed faeces during, or immediately after, the operation ; but this was also done occasionally by the cobras while being gently manipulated and may be due to mere excitement. That the injection had been purely subcutaneous was ascertained by post-mortem dissection in every case, except where otherwise stated. The atmospheric temperature ranged between 8o° and 86° Fah. 20 Scientific Memoirs by Experiments with Cobra-venom on Innocent Snakes. Experiment No. Species of Snake. Length of Snake in inches. Amount of Venom inject- ed (approxi- mately). Result. Duration of life from time of injection. Fost-mortem examination. Remarks. XXV Ablabes rapii l8| | grain Died . 95 mins. Very slight streak capil- lary haemor- rhage at seat of injection. XXVI . Simotes bicatenatus . 26 f gr. and after 4 days i|grs. Doubt- ful. Doubtful . A very strong thick- et snake. Was still alive, although very sluggish se- cond day after last injection, or sixth day after first in- jection. XXVII . Tropidonotus subminia- tus. 22\ 2 gr* Died . 1 1 hours No obvious exudation or discoloration at site of in- jection. XXVIII . Simotes bicatenatus . 8J Igr- „ • 2f „ None made. XXIX . Dipsas gokool . 28^ i? grs. 3t » » XXX Dipsas gokool 3°? 1* » » 4 » » XXXI . Simotes bicatenatus »4i 2 » if days . Very slight in- flammatory ex- udation, but no softening at site of in- jection. Vis- cera general- ly congested, intestines in- jected. ;No bloody fluid in cavities. XXXII . Dipsas hexagonata 32^ 1 gr. „ 5 hours . None made. XXXIII . Dendrophis pictus . 33i !_ » . 55 minutes » XXXIV . Tropidonotus subminia- tus. 3°a grs. ’’ * 55 » ” XXXV . Tropidonotus quincun- ciatus. m igr- 10 hours . At site of injec- tion slight swelling from exud ation, but no haemo- rrhage. XXXVI . Uropeltis, sp. 15 1 2 » ” * 65 mins. None made . A young specime n. Medical Officers of the Army of India. 21 'o'u °Jl Experiment No. Species of Snake. G-~ Q.-T, Seg-3 Result. • 2 g 0 Id Post-mortem examination. Remarks. E g-E £ a 23 0 XXXVII . Gonyosoma gramineum i6J i gr. Died . 85 Mins. None made . Had received con- siderable flesh- wound during cap- ture, but was newly caught and very active. XXXVIII Ablabes collaris . 23 1 » „ • 29 » » XXXIX Gonyosoma gramineum 19 1 „ „ . 45 » Injection proved to be Had received severe wound below neck partially in- tramuscular during capture. (very super- ficially) and attended by slight ca- pillary hae- morrhage. XL Tropidonotus quincun- 37f 2 grs. „ 5f hours. ciatus. Results of these experiments. In all these experiments the cobra-venom proved to be more or less rapidly fatal.1 The duration of life after injection of the venom was in direct ratio (a) to the amount of venom administered, and ( b ) to the robustness of the individual operated on : the more delicate tree-snakes rapidly succumbed, while the relatively shorter but more robust Simotes offered much greater resistance to the action of the venom. The snakes operated on were generally of small size, as the larger soecies of non-venomous snakes, e.g. the python and rat-snake (Ptyas), could not at the time be obtained for experiment. The results recorded by previous observers are shown in the following table. The snakes were bitten by the venomous vere*PenmentS °f previous obser‘ species ; the biting snakes, with two exceptions, being cobras. In addition to those given in the table are three experiments by Fontana2 in which innocent snakes, called respectively ‘aspick,’ ‘adder,’ and ‘ orvai’ were bitten by vipers; but beyond ‘slight torpidity’ in one case no other effect was noted. In experiment No. XXVI the fact of actual death was not ascertained ; but this snake when last seen was evidently dying; and the deaths of two others of the sa me ^species were duly observed — Vide Ex- periments Nos. XXVIII and XXXI. 8 loc. cit., p. 39. 22 Scientific Memoirs by Experiments on Innocent Snakes bitten by Venomous Snakes. Length Duration of No. Biting Snake. Bitten Snake. Observer. of Result. life from Remarks. Snake. time of bite. I Cobra . ‘ Nooni paragodoo ’ (Zamenis fasciolatus ?). Russell 1 . Died ij hours. 2 » ’ ‘ T artutta ’ ( Dipsas tri- gonata ?). ‘ Dhonr ’ ( Tropidonotus » • ’’ 2 „ 3 „ • % • Breton 2 . „ 2? „ sp.1). 4 „ Ptyas mucosus . Fayrer3 . Nil. ... Only observed for one day. 5 ” • ” „ • 8 feet . Died 7 days . 3 days after bite report- ed “ quite well.” 6 ( , . 6 „ . 99 rl 1 a » • Bitten at part where scales scraped off— the cob '-a had just fatally bitten a lizard. 7 » • • »» • Nil. Only observed for one day. 8 } » IM 3) M. Only observed for one day. 9 » • - „ • f Full grown.’ ‘ Large’ » Only observed two days. 10 „ . „ „ „ Had ten ‘ drops ’ cobra- venom (11 days old) injected hypodermi- cally under mm. of mouth. ‘ Several days later ’ it was ‘ quite well.’ 11 „ • „ ‘ Small ’ Died 13 minutes. 12 » • Dendrophis pictus 40 inches }> 9 7 Was not spine crushe d 13 >1 » ‘Smaller’ „ 7 » $ in biting ? than above. 14 ” ' Ptyas mucosus . „ • » 6f hours . Was bitten three times by two cobras. 15 „ Dendrophis ( sp .) . » • ‘ Small ’ „ 41 minutes Bitten by two cobras. 16 » Dryophis (sp.) . 99 3! feet . „ 36 „ >» » 17 „ Ptyas mucosus 99 • ‘ Large ’ „ 27-! hours. 18 n • 99 • ‘ Small ’ „ 21 minutes Twice bitten. 19 „ • Passerita mycterizans . „ • 3 feet . 2 „ “ Body swollen where bitten.” (Qu. from haemorrhage?)No^>osf mortem exam. made. 20 ” • » • ” • * Small ’ ” 17 » 1 Daboia . Ptyas mucosus . . » • ‘ Large’ Died * * After bite ‘sluggish.’ “ Recovered subse- quently.” On seventh day again bitten and died in 1$ days. 1 Bungarus cceru- Ptyas mucosus 2 fe . Died 5! hours . leus. 1 loc. tit., p. 56. I 3 Idem, p. 66 et seq. 2 Idem, p. 170. I Medical O fficers of the Army of India. 2.3 In these experiments the smaller snakes all died more or less rapidly from , the cobra bite, in accordance with the results of my General summary of results. . • 1 1 / own experiments with cobra-venom as previously given. In the case of the large and powerful ‘rat-snake’ ( Ptyas mucosus), however, the results were very varied. This want of uniformity is doubtless in part owing to the experimental errors incidental to biting as a means of intro- ducing the poison, and to insufficiently long observation. But, after allowing for these sources of error, the series of experiments seems sufficient to indicate that the full-grown rat-snake offers a considerable resistance to the action of the venom. Experiments on pythons, and further and more exact experiments on rat-snakes, are desirable. On Lizards. Part V.— Effect of Venom on other Cold-blooded Animals— vertebrate and invertebrate. A considerable number of observations are available under this head. Mitchell refers* to an experiment with rattlesnake venom upon an alligator .... as “ well illustrating .... the activity with which venom may be absorbed by mucous membranes.” Fontana1 2 found that the smaller lizards “ scarcely survive its (the viper’s) bite for a few minutes.” Fayrer3 records two cases of the large water-lizard ( Varanus flavescens ) bitten by cobras with a fatal result in 27 and 46 hours respectively. Wall reports4 a lizard ( Calotes versicolor ) dying in 10 minutes from 40c. of dahoia venom. Fontana3 recorded 1 1 experiments on turtles with the relatively mild viper- n - . . , „ venom : three of the turtles died and eight were On Tortoise and Turtle. . rr & practically unaffected. Cantor6 relates two cases of Tortoise {Trionyx gangeticus) bitten in the lip by sea snakes: the one bitten by a Hydrophis schistosa, 2 feet 9 inches in length, died in 28 minutes ; and the other bitten by a H. striata , 3 feet long, died in 46 minutes. Fontana records7 results of experiments on 86 frogs bitten by vipers, and found that “ some died in less than half an hour, others in an hour, and others again in two or three hours;” And that generally frogs “die in a few hours if bitten by a viper.” Mitchell records8 experiments on ten frogs with crotalus-\e nom and all died : On Frogs. 1 loc. cit., p. 46. 2 loc. cit , p. 41. 3 loc. cit., pp. 68 and 70. 4 'Indian Snake poisons,’ London, 1883, p. 62. loc. cit., p. 39. Trans. Zool. Soc. (Lond.) Vol. II, 1841, p, 310, loc. cit., p. 97 et seq. loc. cit., p. 55. 24 Scientific Memoirs by two dying in an hour, and two living for three to five days. Fayrer gives an account1 of three large frogs ( Rana tigrina) bitten by cobras: two of these died in 26 minutes and in 60 minutes respectively, while the third, which had been bitten by a cobra which had just bitten other animals four times, was reported next day to have “ remained quite well.” Brunton and Fayrer2 give three experiments on frogs with small doses of cobra-poison — the frogs dying within 12 hours. Several other frogs were poisoned by them with cobra-venom to observe the effects on nervous and muscular irritability. Wall reports3 four frogs injected with cobra-venom dying in 40, 67, 79 minutes, and 4 hours respectively; and one frog as recovering from ’77 grs. daboia- venom, while a similar amount of cobra-venom proved fatal in about an hour. Of my experiments on frogs, the leading results are here tabulated. The Own experiments on Frogs. Ven0m WaS in WaterI SoIution and inlected int° the dorsal lymphatic sac. Atmospheric temperature ranged from 8o° to 86° Fah. Control experiments were made on two frogs similar in size to the first two of the series by injecting a similar quantity of water into sac ; but the frogs remained unaffected, and on the second day they were still well. Experiments with Cobra-venom oh Frogs. Amount of Duration of Experiment No. Species of Frog. Size. Venom injected (approxima- Result. life from time of Post-mortem. examination. Remarks. tely). injection. XLI. Ground frog 4 Medium i grain Died. 15 minutes Appearances normal. XLII. V i 13 » • Ditto. XLIII. Bufo galeatus . Large . 1 gr. dried venom. ” 27! hours Wound slightly swollen and One grain freshly dried (without heat) venom congested. was applied to wounded crural muscle through valvular cutaneous XLIV. B. melanostictus Very large. if grs. dried venom. 48 „ • Wound soften- ed and slough- ing. opening1. Applied as above. XLV. Ground frog Largish i grain 99 32 minutes Appearances normal. XLVI. XLVII. Polypedatus ma- Medium 1 „ ” 9 Ditto. culatus . Large . Medium 3 28 „ . XLVIII. Ground frog 1 gr. dried „ 85 „ • Applied as above. venom. XLIX. Polypedatus ma- L. culatus . Large . £ grain 25 Bufo sp. » • i| grains . „ About 11 hours. LI. » ” 4 „ ” 5 hours . 1 loc. cit., pp. 68 and 70. 2 Proc. Roy. Soc., Vol. XXII (1874), p. 73. 3 loc. cit., p. 10 et seq. 4 All the ground frogs used were of the same species — which I have not yet identified. Medical Officers of the Army of India. 25 Fontana found' that from the viper-bite eels “die later” than “the other Q p. h kinds of fish ” he had experimented upon, and not until the end of 18 or 24 hours. Fayrer reports' a case of a fish ( Ophiocephalus marulius ), 14 inches long, bitten near the tail by a cobra dying in 50 minutes. Upon leeches3 spermatozoa and infusoria, on many of the lower forms of ^ plants4 and on cell movement in Vallisneria,