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284 by the access of too much blood to such a degree as to weaken or nullify the anæsthetic influence. Since by this method the anæsthesia can be practically prolonged to an indefinite degree, repeated injections are no longer necessary for that purpose, and the object is attained by the use of comparatively small quantities of cocaine. Hence the danger of constitutional disturbances from overdosing is avoided. Dr. M. J. Roberts has applied the method suggested by Dr. Corning in operations occurring in his practice, with complete success, in cases of excavation of the condyles of the humerus; of an operation on the bones of the leg; and of excision of the hip-joint. In the last case the success was less perfect, on account of the operator having been obliged to use a solution of inferior strength, but was fairly satisfactory. Professor J. Williston and other surgeons of eminence have also used the method with complete success.

Living Encrinites.—The encrinites are among the most interesting of the animals that inhabit the great sea-depths. They formerly played very important parts among the marine fauna, and their remains are found in great masses in the rocks of all the earlier formations. Their shapes, always graceful, now resembling lilies, now palm trees, were wonderfully varied during the primary and secondary periods. They were nearly always fixed to the ground, while, in modern seas, the echinoderms most like them, the Comatulæ, are free, and have forms resembling star-fish, but lighter and more elegant. Encrinites were regarded as extinct till in the middle of the eighteenth century a naval officer brought to Europe a specimen which had been fished up alive. A few years afterward, Guettard described to the French Academy of Sciences another specimen which, dried, is still preserved in the collection of the Museum of Natural History; and, at a later date, some encrinites from the Antilles were distributed among different museums and collections in Europe. But these animals were rare till the time of the American dredging expeditions under Louis Agassiz. It is now known that encrinites, while they are not so abundant as they were in the epoch when limestone-beds were formed out of them, are by no means rare in the deep seas; and zoologists arc in a position to tell geologists what manner of life they lived, and what was the structure of those organisms whose remains are found everywhere, and whose real character once appeared so hard to determine. The discoveries of Sars, in the northern seas, of Pourtales and Alexander Agassiz in the Antilles, and of the various English expeditions, have raised the number of known species of crinoids to thirty-two, which arc divided among four families and six genera.

Geology at the American Association.—Professor Orton delivered an opening address in the Geological Section of the American Association, on "Problems in the Study of Coal; with a Sketch of Recent Progress in Geology." The recent discoveries of the pteraspidian type of fishes in the Onondaga group of Central Pennsylvania, and of scales and spines of fishes (Onchus Clintoni) in the iron sandstone of the Middle Clinton group of the same region, give to American formations the earliest examples of vertebrate life yet known. A living shark has been identified that proves to be so nearly allied to the Cladodus of carboniferous time that it would be doing but little violence to refer it to that genus. Three separate discoveries of Upper Silurian scorpions and a Middle Silurian cockroach carry the life of the earliest land animals a few steps further back than the records of the strata had before disclosed. Two species of pulmoniferous mollusks from the lower part of the carboniferous rocks of Nevada constitute the sole known representatives of that group in palæozoic time. Stratigraphical geology appears to be attaining a somewhat juster recognition than has hitherto prevailed; and the growing use of the microscope in geology is to be noted as one of the directions in which progress is apparent and marked. In the later stages and higher forms of vertebrate life, "American geology holds an easy and undisputed pre-eminence. Along the eastern slopes of the Rocky Mountains there are being disentombed the remnants of great faunas of cretaceous and tertiary time that are quite without parallel in the