INOCULATION AGAINST THE VENOM OF SNAKES. 519 



and this is confirmed by the experiments of Repui {Ann. de Vlnst. 

 Pasteur, Juin, 1895). Thi3 non-absorption is probably due to the fact 

 that the venom does not dialyse through the membranes except with 

 extreme slowness. 



In Mexico certain Indians called Curados de Culebras know how to 

 acquire the privilege of being able to be bitten by the most venomous 

 snakes without the Jeast danger to life, by inoculating themselves 

 several times with the fangs of crotales. During a visit to Tuxpan, 

 Dr. Jacolot, Naval Surgeon, made enquiry respecting these Curados 

 de Culebras and convinced himself that their immunity is indeed real. 



The method of vaccination employed by the natives of Tuxpan is as 

 follows : — 



" A preparatory treatment is necessary. The same day that the man 

 inoculates himself or has himself inoculated, he takes from five to 

 fifteen tubers of a plant known as memo de sapo (toad's hand, Dor- 

 stenia contrayerua). These tubers, and this is very important, must be 

 administered on a Friday, and always an uneven number — five, seven, 

 nine, &c, up to fifteen, according to the tolerance of the subject. 



" If the plant is gathered the first Friday of the month of March, it 

 possesses its marvellous properties in the highest degree ; then, even 

 when dry, it is excellent as a preparation for inoculation. 



" Ordinarily the root of mano de sapo is taken fresh. Another indis- 

 pensable precaution is to abstain, during the period of treatment, from 

 all sexual relations for three days after the second and one day after 

 the third. 



a The inoculation is begun on the dorsal surface of the left foot, taking 

 care not to hit upon a vein. The skin is torn with the extremity of 

 the fang, so that it bleeds a little. From the left foot they proceed to 

 the right fist, then to the right foot and to the left fist, always alter- 

 nating from one side of the body to the other. Then in turn to the 

 right thigh and left arm. 



" All the limbs are thus inoculated. On the trunk an inoculation is 

 made in the median line on a level with the sternum, another at the 

 nape of the neck, and finally one on the head on the middle of the 

 forehead — in all eleven inoculations. 



( - Seven series of such inoculations is the minimum required to protect 

 a man with certainty from the spell of the snake and at the same time 



