��THE POPULAR SCIENCE MONTHLY.
��after-edges, so that when left to themselves they always fell down, and so closed the aperture. Somewhat similar machines have been found in Ireland, north Germany, Styr- ia, and Italy, and their character has been the subject of discussion. They are usually regarded as traps, and it is remarked that all the examples from Italy, Ireland, and Laybach were found in bogs which in earlier times were lakes. If they were really traps, they could be used only in water, where the animal could insert its head from below ; and, among amphibious animals, the otter and beaver are the only ones to which all the conditions involved in a trap theory would apply.
The Qualifications of a Good Norse.
" Now in what," asks Dr. Hal C. Wyman, in an essay on The Training of Nurses, " shall the ideal nurse be trained ? She should have a good education. She need not be schooled in mathematics or philosophy, poetry or sci- ence ; but she must have a good common- school education that will enable her to read any instructions that may be given her, or left with her, in writing; to make records of the condition of the patient, and to write orders for those who may be subject to her. . . . She must be fully acquainted with the English and the metrical system of weights and measures, and she ought to be a good reader, sufficiently well acquainted with the art of elocution to read various selections for the entertainment of her patient. One of the most interesting scenes of hospital life I ever witnessed was that of a Gray Nun in a ward of paralytic and demented patients, reading the news of the day. The soft modulations of her voice, the rapt attention of her listeners, and the agreeable contrast to the listless, weary air of the patients in an adjoining ward I shall never forget." Not only should there be trained nurses in large cities and in connection with large hos- pitals, but they are needed " in communities where there are no large hospitals, in com- munities where there are no hospitals at all, and there ought to be some means of train- ing them on the ground where they are needed. Every county, nearly, has its or- ganization for the medical care of the sick poor. That class, more frequently than any other, needs the tender and supporting min-
��istrations of the nurse. Why not, wher- ever there are physicians employed by the county, have the county physician, with the aid of the superintendents of the poor, or- ganize a school for the training of nurses ? "
Reversion, or Arrested Development.
In a paper in opposition to the doctrine of reversion to a former type, Miss Layard said, in the British Association, that in consider- ing the subject of linear evolution the great importance of a clear understanding of the laws of reversion is apparent ; for, if it can be positively proved that structures common to lower groups occasionally make their appear- ance in man through this means, a strong point has been gained. It is logically certain that there can not be a return to a state which has not once existed. But if, on the other hand, such appearances can be traced to an arrest during the process of develop- ment, or to a sport, the phenomenon shows no connection between higher and lower groups. If we carefully divide positive cases of arrested development and sports from those which may be, strictly speaking, con- sidered to have true appearances of rever- sion, the number diminishes enormously. Perhaps the most important point to be ascertained is as to the limit of time after which reversion to an earlier type becomes impossible. If there be no limit, then it may be a matter of surprise that reversion is not more constant in man.
Storage Reservoirs for the Mississippi.
Captain Eads's scheme of jetties and all other plans for improving the Mississippi River by tinkering with the channel are con- demned by Mr. Jacques W. Redway, in a pamphlet on The Physical Geography of the Mississippi River, as likely to work more mis- chief in the end than they remedy. The au- thor, on the other hand, advocates a plan embodying the storage of the surplus water that accumulates during the spring floods. This will both lessen the volume of the fresh- ets that occur at the breaking up of the win- ter season, and also furnish a supply to be drawn from during the low stage of summer and fall. The storage reservoirs in construc- tion at the present time are mainly the natu- ral basins at the head of the Mississippi proper Chippewa, St. Croix, Crow Wing,