give results which agree, in the main, with each other. In making use of the tables given by Professor Whitney, the most that can be hoped for is a better agreement among themselves of the altitudes computed from observations taken in different conditions of the atmosphere.-Whitney's Contributions to Barometric Hypsometry, p. 42.

THE STADIOMETER.

The stadiometer is the name given by Captain Bellomayer to an instrument invented by him, which is intended to give by one simple reading the length of any line whateverstraight, broken, or curved-as drawn on charts and plans executed on all kinds of scales. The principle of its construction is quite simple. A toothed steel wheel rolling along over the given line makes an endless screw move by means of a pinion. Upon the screw a slider, held in place by friction, is then forced to rise or fall. The graduations are marked upon two faces of the instrument, on the right and left of the slider. The instrument carries eight scales, corresponding to the scales of the French, Prussian, Belgian, Italian, and other national charts, together with the scale corresponding to the natural scale of our meter. Other scales which are less frequently used may be derived from those which are engraved on the instrument. In using the instrument it is held at right angles to the chart, the toothed wheel pressing against the surface of the latter. As the wheel is rolled along over a given line, the slider is, by means of the endless screw, pushed along the graduated scale of the instrument, and the quantity of its movement as shown thereon gives the exact line to be measured on the chart. The principle of the stadiometer has been for a long time known and used. For many years the French Dépôt of Charts and Plans has been accustomed to pay its engravers according to the total length of the curved lines which they trace, measuring these lengths by means of wheels rolling along over the lines; but the instrument devised by Captain Bellomayer replaces these elementary devices by a very portable, convenient, and precise instru ment.-13 B, III., 203.

G. GENERAL NATURAL HISTORY AND ZOOLOGY.

ORIGIN OF ANIMAL FORMS.

Professor Cope in an essay published by the Hayden United States Geological Survey, dated February, 1874, discusses the origin of the great population of animal forms which previous explorations had disclosed in the lake deposits of Wyoming. His conclusion was that they had been derived by migration from the South, as geological investigations pointed to the earlier elevation of the land in that direction. During the summer of 1874, Professor Cope, as paleontologist of the United States Survey under Lieutenant Wheeler, sought for and discovered in New Mexico a great mass of lacustrine deposits, of somewhat earlier age than those of Wyoming, and containing the remains of a great number of animal species and genera, which so nearly resemble those of Wyoming as to leave no doubt that the latter were derived by descent and migration from New Mexico and the South.

In a memoir read before the Academy of Natural Sciences of Philadelphia at nearly the same time, the same writer states. that the primitive type of the mammals with convoluted brains "must have been bunodonts with pentadactyle plantigrade feet;" that is, must have had tubercle-bearing grinders and five-toed feet, whose entire soles were applied to the ground in walking, and not merely the toes, as in most living animals. It was also stated that variations in the number and relations of the front teeth might be expected in such a hypothetical group of animals, which was named Bunotheriidae. During the explorations in New Mexico the following season a remarkable genus was discovered, and afterward named Calamodon. Its jaws and teeth were obtained, and the latter had tubercle-bearing crowns. Subsequently Professor Marsh described more perfect specimens, which show that this animal was also five-toed (pentadactyle), and walked on its soles (plantigrade). With other similar genera he forms an order Tillodontia, and says that they are related to hoofed animals (Ungulata) and Carnivora, and

that their brains were somewhat convoluted. This is a very full confirmation of the anticipation by inference above mentioned. It was then stated that the primitive Ungulate "can not be far removed from the primitive Carnivore and the primitive Quadrumane." Two other genera discovered by Professor Cope show that great variations in the number of the front teeth exist in these animals, some having one, and some two pairs of incisors, etc.

THE CELL-STRUCTURE OF ORGANIC TISSUES.

Professor Redfern, at the late meeting of the British Association, called attention to the changes that have taken place in the views of scientific men in regard to the cellstructure of organic tissues since the days of Schleiden and Schwann. At that time the separation of groups of cells by a basement membrane was considered to be an important physiological condition; such groups, retaining individuality, carry on their life, and even pass into such diseased conditions as cancer, without influencing or being influenced by neighboring structures. Now all is changed, and the idea of a cell as a vesicle has given place to that of a solid corpuscle. Graham has taught that all the tissues are permeable, and continually permeated by fluids carrying nutrient material; and we more lately learn that the living corpuscles can wander out of their positions of attachment, enter the blood current, and again pass from the blood-vessel through its soft and viscid wall. There indeed seems to be evidence that the finest filaments of nerves end in the living corpuscles or cells, especially in the olfactory and gustatory cells, and the skins of fishes. According to Professor Redfern, the statement of Pflüger that the nerves terminate in the cells of the salivary and pancreatic glands, although probable, has not yet been positively established.-15 A, August 29, 1874, 279.

RAPID DEVELOPMENT OF INTRODUCED ANIMALS AND PLANTS.

It is well known that certain plants, when grown in new countries, exhibit a remarkable development vastly exceeding that which takes place in their native soil. This is evidenced in the character of eastern vegetables when grown in California, of which such marvelous tales are sometimes related. The same thing appears to exist in a greater or less

extent in the case of animals, especially in fishes, particularly where transported to countries in which that particular group was originally wanting.

Wonderful tales are told of the rapidity of growth of the German carp in California, to the effect that they will become as large in one year as they do in Germany in three or four, and be capable of reproduction in the same period. However this may be, we are assured that the success which has attended the introduction of the English trout into Australia has been quite remarkable. A recent writer states

that in November, 1872, about 400 fry were turned out at Ballarat, having been hatched in the month of September previous. In January, 1875, or twenty-six months after being liberated and twenty-nine months after hatching, some of these fish were taken in a net, one of them, a female, weighing an ounce less than 10 pounds; two others turned the scales at 9 pounds, two at 9 pounds, and four or five others averaged 74 pounds each; and the smallest fish taken weighed over 6 pounds, and all were in splendid condition.

A somewhat similar experience was had in the case of certain perch, the progenitors of which had been brought the year before from England. Three years previous a sodawater bottle, filled with eggs of perch, was placed in a lagoon at some distance from Ballarat. The fish hatched out, and quite lately several specimens weighing 5 pounds and upward have been taken.-19 A, April 24, 405.

INFLUENCE OF THE ROOTS OF LIVING VEGETABLES UPON

PUTREFACTION.

Jeaunel states that the project for utilizing the waters of the sewers of Paris by allowing them to flow over 2000 hectares of cultivated fields, near Paris, has caused some apprehensions on the part of sanitarians. In reply, one may inquire why the neighboring island of Jennevillius, receiving, as it does, the enormous quantity of 240,000 cubic meters of putrid water, should not be a dangerous centre of infection, and menace the health of the populations of all the neighboring suburbs, and even of Paris, the northwest quarter of which is only two kilometers distant from the irrigated lands. This great question seems answered by experience. The inhabitants of the villages above quoted, the laborers who live upon

the soil fertilized by the sewerage, are not subject to any of the maladies which it is customary to attribute to it, such as typhoid fever, malarial fevers, etc. This immunity doubtless results from the fact that the vegetables cultivated there are themselves powerful agents of purification. But science does not yet show precisely how they bring this about. The fact, however, that cemeteries, bogs, and marshes are made salubrious by vegetation is indisputable, being purely the result of experience. His own theory is that the roots of growing plants have the power of arresting the putrefaction of all organic matters held in suspension or in solution in the water; that these roots of living vegetables are sources of oxygen, since under their influence the bacteria and monads, as well as putrefying and fermenting matters, disappear, and are replaced by the infusoria which live in relatively wholesome water. Experience, in fact, directly confirms common opinion which attributes to vegetables the power of rendering wholesome the soils impregnated with putrefying animal matters.-Bulletin Hebdomadaire, XVI., 79.

COLLECTIONS OF FOSSILS FROM THE COAL-MEASURES OF OHIO.

Professor Newberry, director of the geological survey of Ohio, has lately made additional collections in the fossilbearing coal-measures. Land vertebrate remains of that age within the limits of the United States have as yet been only found in Ohio, and the specimens are noted for their singu larity and beauty. Thirty-three species of batrachia have been found, but no reptiles nor higher vertebrata. One of the novelties is a species of the genus Ceraterpeton-the first time a European genus of fossil batrachians has been detected in this country. This form is as large as a rat, and has a pair of stout horns on the back of its head, in the position and having much the form of those of the ox. The skull is sculptured by rows of small pits, separated by fine radiating ridges.

LIVING ANIMALS CORRESPONDING TO THOSE OF PREHISTORIC

AGES.

The discovery of a living species of ganoid or dipnoan, fish of the triassic period, recently made in Australia, attracted much attention at the time. It is the Ceratodus forsteri of