Page:Popular Science Monthly Volume 17.djvu/735

This page has been validated.

out the country, and has been attended by great advantages to the Harvard school. The classes have grown constantly larger, and the quality of the students has improved in nearly the same degree. An admission examination was instituted soon after the new course was adopted, and has recently been made considerably more efficient. The faculty now find that the three years which are allotted to the course are not enough to permit a thorough mastery of all the branches which it embraces, and contemplate adding a fourth year. For the present, the additional year will be optional with the student, who may either crowd all he can into three years as before, or take more time for what has hitherto been attempted in that period, and pursue the special studies which are additionally provided for the fourth year. In the schedule of studies under the new arrangement the main studies of the third year are continued into the fourth year, and an examination will be held at the end of the latter year in a number of special branches, the instruction in which is intended to be more clinical and individual in character than that heretofore given and to take the place partly of the private teaching which American students have heretofore sought in European schools after graduation.

The Cutting Ant.—The Rev. H. C. McCook, of Philadelphia, has made a very interesting study of the cutting or parasol ant (Atta fervens, Say), having encamped for the purpose close by its haunts near Austin, Texas. The habitation of the insect was marked by a bed of denuded earth on the prairie, measuring in the case of the one specially examined eight feet nine inches by about seven feet. Over this denuded surface were scattered between twenty and thirty circular, semicircular, and S-shaped elevations of fresh earth-pellets, the circular ones resembling a spittoon three or four inches high, which had apparently been formed by the accumulation of the pellets of sandy soil as they were brought out and dumped upon the circumference of the heap. No life was noticed around the colony during the day, but earthen knobs or warts, and small, irregular heaps of dry leaves, bits of leaves and twigs were noticed scattered over the surface. As evening began, the scene was wholly changed. "Hosts of ants of various sizes, and in countless numbers, were hurrying out of open gates into the neighboring jungle, and two long, double columns were stretched from the bottom to the top of the large overhanging live oak. The ants in the descending columns all carried above their heads portions of green leaves, which waved two and fro and glanced in the lantern-light, giving to the moving column a weird look as it moved along. It seemed like a procession of Liliputian Sabbath-school children bearing aloft their banners. It is this habit which has given this insect in some quarters the popular name of the 'parasol ant.' It is also called in Texas the 'Brazilian ant,' but is quite universally known as the 'cutting ant,' certainly a most appropriate name." The heaps of leaves and twigs lying around the habitation were the closed gates. The opening and closing of these gates occurred before and after every exit from the nest. The process was a long, careful, and complicated one, the opening beginning toward evening, and the closing ending in the morning, sometimes as late as half-past ten. Toward dusk, the minims, or smallest ants, would appear, taking away from the heap particles of sand; larger forms followed carrying away bits of refuse, which they dropped at about two inches from the gate. Finally, the throng would rush out, bearing before them the rubbish, which after a few moments was cleared away from the gallery and spread around the margin of the gate. The litter thus taken away was brought into use again when the gates were closed. In closing the gates, the larger forms did their work first, bringing in twigs, some as long as an inch and a half, and dried leaves, which they deposited to the depth of from a half-inch to an inch and a half below the surface. As the hole was gradually closed, only the smaller forms appeared, and the last touches were carefully and delicately made by the minims, which filled in the remaining interstices with minute grains of sand. A division of labor was noticed in the work of cutting and carrying the leaves. The party consisted of soldier-ants, seeming to act as escort and scouts, the cutters, and the carriers, who took the cut leaves from the base