The habitat frequently furnishes a key to the character of the snake. The venomous varieties choose by preference the rocky uplands, either open or sparsely wooded. The harmless snakes live almost exclusively in low swampy lands or along water courses. Venomous snakes are purely terrestrial. One was never known to ascend a tree. In fact it is impossible for one to do so.
While rattlesnakes are dangerous, their bite is not nearly so fatal as is popularly supposed. This fact has at least two important reasons, viz., season and the habits of life of the snake. In the extreme South and in midsummer the venom attains its highest state of virulence. Then the person fairly struck by a large rattler is in extreme danger, provided the second factor in the equation does not intrude, that is, the habits of life.
All venomous snakes, and more especially rattlesnakes, are sluggish. They do not move rapidly or over great distances. Their lethal power is given them as a means of procuring food and when once the snake strikes he expends practically all the ammunition in his arsenal. It requires hours and perhaps days to renew the supply, during which time the serpent is defenseless. Should the human victim happen along at such time and be bitten it is quite probable that he would not receive a fatal dose of the poison.
The manner in which the rattlesnake inflicts his wound is worthy of some study. In the first place, it may be assumed as axiomatic that the snake cannot strike farther than his own length and seldom even that. Stories of rattlesnakes lifting themselves from the ground bodily and hurling themselves through the air are purely imaginative. Nor can the snake strike unless coiled. It does not follow that he must be in complete coil, but he must have at least a few kinks in his spine before he can deliver a blow; then he can only strike the length of the kinks.
If permitted he will assume full coil before striking and when undisturbed he lies in that position. The maneuver of assuming full coil takes longer than is generally thought. Writers who assert that the snake can throw himself into full coil instantly are far from the truth. In fact it takes, on an average, something like five seconds for him to get his length in position to deliver his most powerful blow. My experiments have developed another interesting fact, that the snake cannot strike an object held directly over his head. It must be held at an angle.
How deep will the needle-sharp fangs penetrate. That depends, too, upon conditions. A large snake, striking from full coil, will naturally drive his fangs much deeper than another smaller, striking from a less advantageous position. Upon the bare flesh the snake will sink his fangs to their full extent. His blow, however, is often delivered with a raking motion and the wound inflicted resembles the scratch of a briar.
Certain articles of dress are less permeable than others. Rubber, even thin rubber, is wellnigh impenetrable. Soft, closely woven cloth is also resistent. In experiments I have placed blotting paper behind two thicknesses of heavy flannel and only in rare instances have I found the virus staining the paper. This fact will serve to inform the reader that the ordinary protection of the lower limbs will be adequate to shield the wearer in a rattlesnake country.
The chances of being bitten, even in a country abounding in snakes, are really quite insignificant. The rattler is the most inoffensive gentleman of my serpentine acquaintance. He is perfectly willing, if you will permit him, to lie all day basking in the sun upon some convenient rock and never molest the passer in the least. If he has sufficient warning he will slip quietly out of your path and give you the right of way. He only strikes when in his reptilian mind he deems himself insulted or in danger.
An extended discussion of the chemistry of serpent venoms would be manifestly out of place at this time. We owe practically all our knowledge upon the subject to the painstaking efforts of two men, S. Weir Mitchell and Prof. Reichert. These gentlemen gave to the world almost simultaneously the result of their labors. The lethal principle of all serpent venoms consists of two elements, a venom peptone and a venom globulin.
These elements are albuminoid in character, and it is interesting to note that they act no differently from the pure albuminoses of digestion. One element has the power to destroy the fibrin ferment in the blood, the other acts as a paralyzant upon motor and sensory nerve trunks.