August 20, 1896J 



NA rURE 



381 



1 in 60— for the local treatment of snake bites, to prevent the 

 absorption of the venom. 



Quite recently M. Phisalix, assistant in the Paris Museum, 

 has announced that he has succeeded in separating the vac- 

 cinating substance of venom by filterini; it through a Chamber- 

 land filter. The animals into which this experimenter inoculated 

 the filtered venom did not die, and he found that they were 

 vaccinated against the inoculation of a lethal dose of non-filtered 

 venom. I have repeated these experiments with the greatest 

 care, but the results that I have obtained are very different from 

 those obtained by M. I'hisalix. When a solution of normal 

 venom is filtered through a Chamberland bougie a great part of 

 the venom is kept b.ick by the porcelain, just as is the case 

 when microbic toxines are similarly filtered. It is certainly 

 found necessary to use two and a half times more of the filtered 

 venom than of the non-filtered venom in order to kill animals of 

 the same weight ; but if before filtration care is taken to separate 

 the albumin of the venom by heat, it is found that the porcelain 

 no longer keeps back any of the toxic substance. The animals 

 are killed by the same dose of solution both before and after 

 filtration. It follows very evidently, therefore, if the venom 

 which has not been freed from albumin is less toxic after filtration 

 than l)efore, that this must be due to the fact that the albumin 

 adheres to the porous wall of the filter, so forming a perfect 

 ilialysing membrane through which the venom can pass only 

 with very great difficulty. I have been able to prove this by 

 restoring a certain proportion of albumin by means of the 

 addition of normal serum to venom that had previously been 

 deprived of its albumin by heat. On filtering this venom con- 

 taining the added albumin, I found that the liquid which passed 

 through the filter was again considerably less toxic. Animals 

 which have received filtered venom, and which have not 

 succumbed after the lapse of three days, resist a minimal 

 lethal dose of venom — i.e. they do not die ; they are already 

 vaccinated, just as are those that have been injected with a less 

 than lethal dose of normal venom. There is, I believe, no 

 reason to suppose that, as has been maintained by Phisalix and 

 JJertrand, there is brought about by heat or by filtration of venom 

 any separation of two substances, the one toxic and the other 

 vaccinating, which are supposed to be found together in normal 

 venom. This hypothesis does not appear to me to be justified 

 by experiment, and it is absolutely certain that if one inoculates 

 an animal with a quantity of heated %-enom, or of filtered venom 

 of which the toxicity has been modified in sufficient quantity to 

 kill the animal, it will react exactly as if it had been injected 

 with a dose of normal venom a little below that required to 

 produce death. In both cases, and in the same time, the animal 

 acquires through this inoculation a state of resistance which 

 enables it, at the end of several days, to receive with impunity 

 an amount of venom capable of killing animals of the same 

 weight. The serum of animals vaccinated against one species 

 of very active venom, such as the venom of the cobra for 

 example, is perfectly antitoxic as regards the venom of all other 

 species of snakes, and also, as I have been able to prove, against 

 the venom of scorpions. 



The best method of procedure for the purpose of vaccinating 

 large animals destined to produce anti-venomous serum consists 

 in injecting them from the outset with gradually increasing 

 quantities of the venom of the cobra mixed with diminishing 

 <iuanlilics of a I in 60 solution of hypochlorite of lime. The 

 condition and the variations in the weights of the animals are 

 carefully followed in order that the injections may be made less 

 frequently if the animals do not thrive well. Quantities of 

 stronger and stronger venom are in turn injected, first con- 

 siderably diluted and then more concentrated, and in order that 

 the animals (horses) may give a .serum equally active for the 

 various phlogogenic substances which determine the various 

 local actions it is neces.sary, when they have already acquired a 

 sufficiently perfect immunity, to inject the venoms derived from 

 as large a number of difi"erent species of snakes as possible. 

 The duration of the treatment is of considerable length, at least 

 fifteen months, before the serum is sufficiently active to be used 

 for the purposes of treatment. The serum that we actually 

 pr-'lMre at the Institut Pasteur, Lille, is active to the degree of 

 l/20o,ooolh, that is to say, it .suffices to inject, as a prophylactic 

 dose, into a rabbit a quantity of serum equal to the 200,000th 

 part of its weight in order to protect it against a dose of venom 

 killing an animal of equal weight in three or four hours. If this 

 serum be injected after the venom, it is sufficiently active in a 



NO. 1399, VOL. 54] 



dose of 4 c.c. given thirty-three minutes after the inoculation of 

 a dose of venom lethal in three or four hours to prevent the 

 death of the animal. Large quantities of this serum have been 

 sent during the last few months to India, to Cochin China, to 

 .Australia, and to other countries where venomous serpents are 

 most frequently met with, and we have already been able to 

 collect certain interesting observations on people bitten. It is, 

 however, very difficult in the greater number of instances to 

 obtain information as to the species of venomous snake that has 

 inflicted the wound. It has seldom been found possible to kill 

 or capture on the field the snake inflicting the bite, so that all 

 the statements as to the species of the snake which have not 

 been so determined must be considered as open to some 

 suspicion. I have already published one case, a most conclusive 

 one, that of an Annamite bitten very severely in the hand by a 

 cobra at the Bacteriological Laboratory of Saigon, who was 

 cured by a .single injection of 10 c.c. of serum. I have quite 

 recently received the report of another very interesting case, for 

 which I am indebted to Mr. Hankin, director of the laboratory 

 of Agra in India. The patient in this instance was bitten by 

 one of the most dangerous reptiles found in India, the Bungarus. 

 It has, indeed, been fully demonstrated, both by experiments 

 on animals and by the actual treatment of snake bites in the 

 human subject, that we have in anti-venomous serum a '• specific " 

 remedy which is very efficacious against venomous biles. It 

 is, therefore, surely necessary to hasten to distribute it in 

 all those countries where dangerous snakes are found. The 

 only real difficulty consists in procuring sufficient quantities of 

 venom for the immunisation of large animals, such as horses, to 

 furnish adequate quantities of serum. The Pasteur Institute at 

 Lille actually possesses enough venom, and horses completely 

 immunised numerous enough for the most pressing wants. 

 Serum prepared in an absolutely pure condition can be preserved 

 for more than a year without, losing any of its curative proper- 

 ties. In all countries where snakes claim their numerous victims, 

 and especially in India, where the annual nuiriber of deaths 

 resulting from venomous bites rises to about 22,000, it would 

 surely be expedient that the various tiovernments should take 

 steps to establish depots, at least, in the principal agricultural, 

 forest, and mining districts, where medical aid may be afforded 

 as early as possible to every person bitten who comes to seek 

 treatment. Each of these posts should be supplied with (i) a 

 stock of serum, renewed each year ; (2) hypodermic injection 

 syringes ; (3) a perfectly freshly prepared solution of hypochlorite 

 of lime, and other medicaments and instruments necessary for the 

 dressing of wounds. The expense of effecting such an organisa- 

 tion would be very slight. I ask you, gentlemen, to pass 

 unanimously a resolution that may have the effect of inducing, 

 or affording justification to, the Indian Government to realise 

 this huinanitarian scheme. 



Dr. Calmette delivered a lecture, with experimental illus- 

 trations, in the Laboratories of the Conjoint Board of the Royal 

 College of Physicians and Surgeons, on " The Treatment of 

 Animals poisoned with Snake \'enoni by the injection of Anti- 

 Venomous Serum." In the course of his lecture he said : 



I have to-day the opportunity of giving you the results of 

 experiments that have been performed under Dr. Woodhead's 

 licence, but under my direct personal .supervision, so that they 

 may be depended upon as affording direct proof of the value of my 

 method. Those animals that have been successfully treated you 

 may examine for yourselves ; others that have been poisoned 

 with the snake venom, but have not received the serum, have 

 succumbed ; these latter serve as contiol experiments with 

 which to compare the results obtained when the serum has been 

 given. 



These experiments are easily carried out, and are absolutely 

 painless. In rabbits, as in the human subject, the first symptom 

 indicating the action of snake poison is slight somnolence, 

 which, becoming more and more marked, is gradually succeeded 

 by a condition of unconsciousness associated with, first, muscular 

 contraction and then with loss of motor power, which, com- 

 mencing in the hind limbs, passes forwards until the respiratory 

 centres are affected, the cardiac centre being the last attacked. 

 When the animal dies, the heart is found in a condition of 

 diastole. The venom may be injected in two ways — intra- 

 venously, when a comparatively small dose acts with great 

 rapidity ; and .subcutaneously, when the dose also acts power- 

 fully but more slowly. ,\ lethal dose of cobra poison injected 



