The interesting invalid, ordinarily tame and gentle, had latterly displayed anger and irritability on being disturbed, pushing away the hand if touched; but in her present state the want of water was so great that she evinced uneasiness to her guardian, and permitted him to move and turn her head, so that she could dip the end of her muzzle into the basin. The narrator argued, from this remarkable demonstration, that the incubation (in which a rise of temperature was observable) produced a sort of feverishness which caused her to decline solid food, though her thirst was so great that she almost asked for drink.
When eight of the fifteen eggs were hatched, the little pythons ate nothing until after their first moult (which happened to them all within a fortnight), but during those early days of their existence they ‘drank several times, and also bathed themselves.’
This event perhaps established the fact beyond any doubt that snakes do drink, so far as modern and scientific ophiologists had ventured to decide; and M. Dumeril, from long observation, is able to tell us how.
Speaking of the tongue of a snake, this experienced naturalist informs us that ‘cette langue fort longue sert-elle comme on l’a observée quelquefois à faire pénétrer un peu de liquide dans la bouche, car nous avons vu nous-même des couleuvres laper ainsi l’eau, que nous avions placée auprès d’elles dans la cage, où nous les tenions renfermées pour les observer à loisir.’[17]
But, as he goes on to describe, ‘quelques serpents avalent de l’eau sans se servir de la langue pour laper. Alors ils tiennent la tête enfoncée sous l’eau au-dessous du niveau, ils écartent un peu les mâchoires, et font baisser le fond de la gorge, dans laquelle l’eau descend par son propres poids.’ You can then perceive the slight movements of swallowing, like a thirsty man gulping down a beverage (à la régalade).
What follows affords an explanation of M. Schlegel’s statement that he had never discovered water in a snake which he had dissected, this learned author not having gone so thoroughly into the matter. ‘Cette eau,’ says M. Dumeril, ‘sert à laver les intestines; car elle est rendue liquide avec les fèces, elle ne parait pas expulsée par les voies urinaires.’
M. Dumeril speaks very clearly on this point both in his introductory preface, and again in vol. vi., under the more detailed descriptions of each especial sense and organ.
Snakes rarely drink (that is, not every day, as most animals do), most of them living in dry regions or forests, where for long periods they are deprived of water. The live prey upon which they subsist supplies them with sufficient liquid. This may be known by the natural discharges, which are usually of a liquid nature. Nevertheless, a large number of serpents live close to water, and love to plunge and to swim. These truly drink,—lapping with the tongue, as above described; at other times with the head under water, and the neck still lower, so that the water falls into the mouth by its own weight, and is then swallowed. But this, he repeats, does not go into the blood, or very little of it, car ils rendent en grand partie, etc., as above, its function being principally to moisten the intestines.
Lenz, a German ophiologist of still earlier date than Schlegel, went very conscientiously into the subject of whether snakes drink or not,[18] having adopted various means in order to test them. His personal experience was, however, of a more limited range.
It is worth while to bear in mind the dates of some of these writings, both that we may watch the gradual advance of ophidian knowledge, and also that we may the better appreciate the vast amount of time, care, labour, and research by which we are finally put in possession of facts of natural history.