It really seems, therefore, that the resistance of the hedgehog to venom is due to the presence of antitoxic substances in its blood. But, as in the case of the mongoose, there is no question here of genuine _immunity_. The same is probably true with respect to the herons of Colombia, the _Culebrero_ and _Guacabo_, which eagerly search after young snakes for food. No investigations, however, have yet been made upon this subject. These birds, moreover, are few in number; hunters pursue them for the sake of their brilliantly coloured plumage, and it is to be regretted that no attempt is made to prevent their destruction or to acclimatise them in countries in which poisonous snakes constitute a veritable calamity, such as Martinique, St. Lucia, or India. CHAPTER XII. _SNAKE-CHARMERS._ In all the countries of the globe where poisonous snakes are formidable to man, there are certain individuals who profess to be secure from all ill-effects from the bites of these reptiles, whether because they are immune to venom, or because they possess secrets which enable them to cure themselves when they happen to have been bitten. Not unnaturally these secrets are sometimes turned to profitable account, and the possessors of them generally enjoy considerable popular influence, and are very highly venerated. Intimate relations with the divinities are freely attributed to them. Among the Romans the jugglers who carried on the profession of snake-charmers and healers of snake-bites were known as _Psylli_. Plutarch tells us that Cato, who loved not doctors because they were Greeks, attached a certain number of them to the army of Libya. They were accustomed to expose their children to serpents as soon as they were born, and the mothers, if they had failed in conjugal fidelity, were infallibly punished by the death of their offspring. If, on the contrary, the children were lawful, they had nothing to fear from the bites of the reptiles. “_Recens etiam editos serpentibus offerebant; si essent partus adulteri, matrum crimina plectabantur interitu parvulorum; si pudici, probos ortus a morte paterni privilegium tuebatur_” (Solinus). The Libyian Psylli of antiquity still have their representatives in Tunis and in Egypt. Clot Bey writes as follows with reference to the Egyptian Psylli:-- “The _Ophiogeni_, or Snake-charmers, have been renowned from all time. Strabo speaks of them, and Prosper Alpinus was a witness of the singular effects of their art. The majority of modern travellers who have visited Egypt have been equally struck with the freedom with which they handle poisonous reptiles and animals.