This is curious and noteworthy. The power or volition which can control the sheath and close the valve can, no doubt, exclude these foreign particles; as, while lapping, the mouth must be moistened as well as the interior of the sheath, both it and the tongue requiring frequent lubrication.
But we have now reached the confines of speculation. There is enough of real fact about this ‘horrid forked tongue’ to interest and astonish us. We find it guarded, aided, especially provided for, and especially constructed and endowed; especially harmless also. To the owner its importance ranks not second even to the eyes.
The importance of the antennæ to insects is evident to all who have ever watched the play of those active and beautifully-elaborate organs, their infinitely varying forms (often many times the length of the insect itself), their ceaseless play and independent action. Constantly waving, they lightly touch every contiguous object; investigating on all sides, they convey to insect intelligence all it requires to know regarding its environments. Like a herald or a scout, they literally ‘spy out the land,’ and thus become a guide and a guard to the tiny feeble creature which possesses them. Through them the owner learns all that is needful for its well-being.
Much as an insect uses these exquisitely-constructed antennæ, so does a snake its long, slender, pliant, bifurcate, and highly-sensitive tongue. Ever busy, ever vigilant, exploring while barely touching each surface within reach, yet by night and by day conveying with that slight contact all necessary information to its owner. Sent out with the speed of a flash, it telegraphs back with like quickness the result of its discoveries.
If we may assign intelligence to any single organ, we might affirm that there is more of what we consider rational intelligence in the tongue of a snake than in any other of its perceptive faculties. Probably the most important knowledge demanded by the reptile is conveyed, or, at least, confirmed by this organ.
‘Colorée,’ says Dumeril of the tongue, as botanists say of the part of a plant ordinarily green, as, for instance, a calyx; ‘coloured,’ but not what colour. This is precisely as we may describe the colour of a snake’s tongue. My attention was first drawn to this on reading one of Dr. Arthur Stradling’s communications to Land and Water, April 2, 1881. ‘It would be interesting to know why some snakes have red tongues and others black,’ he writes. ‘Here beside me, in a glass case, are two little snakes, both belonging to the same genus (Tropidonotus)—a seven-banded (T. leberis), and a moccasin (T. fasciatus), both hailing from the United States, and both alike in their habits and choice of food; yet it is a case of rouge et noir with their lingual appendages.’
After reading this, I noticed the varieties of colour in all the ‘forked tongues’ that exhibited themselves at the Zoological Gardens. Black or very dark tongues, I think, predominate; and next to black, brownish or olive tints, resembling those of the snake itself. But not as a rule; for some very light snakes have dark tongues, and the converse. In two small green tree snakes of distinct genera, one had a pale pink or flesh-coloured tongue, and the other a black one. Some tongues are almost white, while a few are red. There seems to be as much caprice as in the colour of the human hair and eyes; and as physiologists have traced some sort of connection or relationship with complexions and constitutions in these, so ophiologists may, after a time, discover a similar relation or sympathy between the colour of a snake’s tongue and its integument or eyes. At present, I have observed only so far as that two entirely black and two entirely green snakes may present four distinct colours as regards their four tongues, and that many tints of brown, black, and pink may be seen in the tongues of as many snakes.
