Page:Popular Science Monthly Volume 17.djvu/296

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284
THE POPULAR SCIENCE MONTHLY.

nary temperature (65º to 75º), a cold room (40º), and a hot room (90º), and the watches are tested in the vertical and horizontal positions. Eight classes of certificates are given, corresponding with different combinations of the several tests and their relative duration. In cases where no certificate can be given the movement will be returned to the maker, with a statement of its performance.

 

Snakes and Snake-Poison.—Professor Huxley, in a lecture on "Snakes," at the London Institution last December, said that no creatures seemed more easily destroyed by man and few less able to defend themselves; yet there were not many animals gifted with so many faculties. The snake can stand up erect, climb as well as any ape, swim like a fish, dart forward, and do all but fly in seizing its prey. The destructiveness of snakes to man is illustrated by the fact that twenty thousand human lives are yearly lost in India by their poison, and it might safely be said that they are a more deadly enemy to our race than any other animals. The speaker pointed out some very curious arrangements in the anatomical mechanism and jawbones, illustrative of the statement that the snake can not properly be said to swallow his prey; he holds on to it rather, gradually working it down its throat in a most leisurely manner, but never letting it go. He requires a very fully developed and effective apparatus of salivary glands for this purpose. The poison-bag of the venomous snakes is nothing but a modification of the salivary glands of the harmless species, the structure of both kinds being in almost all respects not only parallel throughout, but almost identical. As another instance of the close relationship, it was shown that the sharp channel-needle which conveys the poison of the cobra and its congeners is nothing but the development of the tooth which these murderous reptiles possess in common with innocuous snakes. The fact that the salivary gland was the poison laboratory of the deadly snakes, as well as the known properties of the saliva of dogs or other living creatures affected with rabies, appeared to Professor Huxley to point out the direction in which lies the solution of the difficult problem of the cause of snake-poisoning, and of a possible antidote against it. At present there was no man living who could heal the bite of the cobra, except by cauterization in very fresh cases. A fitting supplement to Professor Huxley's remarks is afforded by facts given in the reports of the Snake-Poison Commission of Calcutta, showing the number of snakes killed, and of deaths by snakes and wild animals in India. In 18*75, 270,185, in 1876, 212,371 snakes were killed in all India. The deaths by snakes and wild animals were 21,000 in 1875, 15,946 in 1876. These figures do not give the whole numbers, for the registries are incomplete in the English districts, and no registries are kept in the native states, so that it may be found hereafter that many thousand deaths must be added to complete the catalogue of annual disaster from snakes. The excess of numbers in 1875 is accounted for by the fact that the floods of that year drove the snakes to the high-roads and exposed places. Remedies are said to be known for the poison of all the snakes except the cobra.

 

Development of the Limbs of Saurians.—Professor O. C. Marsh has noticed some peculiarities in the limbs of the sauranodon, the new saurian described by him in January, 1879, which give it a special interest. Both the anterior and posterior limbs are less specialized than in any other known vertebrate above the fishes. In the fore paddle, the humerus alone is differentiated. Below this, the bones of the forearm, the carpals, metacarpals, and phalanges are essentially rounded, free disks, implanted in the primitive cartilage. The structure of the posterior limb is substantially the same. The most striking features of the limbs are the presence of three bones next below the humerus and the femur and articulating with them, corresponding apparently with the radius, intermedium, and ulna in the fore-limb, and with the tibia, intermedium, and fibula in the hinder limb, and the fact of six digits. These characters are held to mark a stage of development below that seen in any other air-breathing vertebrate, and only approached by the limb of the icthyosaurus. The intermedium seems, in the process of differentiation, to have been