It is precisely this desideratum that J. Morgenroth has succeeded in realising, by means of hydrochloric acid, which renders it possible to dissociate the neutral mixture, _toxin_ + _antitoxin_, into its constituent elements, and then to obtain a _lecithide_. Experiments show that the quantity of lecithide thus restored absolutely corresponds to that of the cobra-hæmolysin originally added to the antitoxin, and that the antitoxin set free is not injured by the hydrochloric acid, even after twenty-four hours of contact. It is sufficient to add the quantity of soda or of ammonia necessary for the neutralisation of the acid, in order to see the antitoxin reappear in its original strength. It is therefore possible, by causing hydrochloric acid (in a solution not stronger than 3 per cent.) to act on a neutral mixture of cobra-hæmolysin (toxin) and antitoxin, to set the former at liberty in the form of _lecithide_, to withdraw the latter from the action of the antitoxin, and to demonstrate its presence, owing to its hæmolytic properties. It has been found by Kyes and Sachs that, under the influence of hydrochloric acid, cobra-hæmolysin becomes resistant to heat to such an extent that it is not destroyed even by prolonged heating at 100° C. If to a neutral mixture of toxin + antitoxin we add a small quantity of hydrochloric acid, and then heat the mixture at 100° C., the antitoxin being in this case destroyed, we shall recover the whole of the toxin originally employed. Therefore, as was shown by me so long ago as 1894, if the mixture of toxin + antitoxin produces a chemical combination between the two substances, this combination is unstable, and can be effectively broken up into these two constituent elements by various influences. CHAPTER XV. _TREATMENT OF POISONOUS SNAKE-BITES IN MAN AND ANIMALS._ _OBJECTS OF THE TREATMENT: TECHNIQUE OF ANTIVENOMOUS SERUM-THERAPY._ In all countries the remedies recommended for the bites of poisonous snakes are innumerable, and native pharmacopœias abound in so-called infallible recipes. Pliny himself wrote on this subject as follows:-- “For poisonous bites, it is customary to employ a liniment made of fresh sheep-droppings, cooked in wine. Rats cut in two are also applied; these animals possess important properties, especially at the epoch of the ascension of the stars, seeing that the number of a rat’s fibres wax and wane with the moon. “Of all birds, those that afford most assistance against snakes are vultures. The black ones are the weaker. The odour of their feathers when burnt puts snakes to flight. Provided with a vulture’s heart one need not fear encounters with snakes, and can also defy the wrath of wild beasts, robbers, and princes.