blueness returned if the window was shut for any time. It was directed to be kept open night and day, and I could see from my house that this order was carried out. Although on one night the thermometer showed 14° F. of frost the chest was clear of noises and she was convalescent in eight days. If fresh air needs warming she ought to have died. Why do most men feel so tired after an afternoon's work in a crowded out-patient room? Why is a long journey in a full railway carriage, even with a comfortable seat, so exhausting to many people? Personally an hour or two in a full carriage with the windows shut will give me numbness in my feet and legs and knock me up for the day, while a railway journey in an empty carriage with open windows does not affect me at all. But most people will be willing to admit that any kind of crowd is tiring. It is to me difficult to resist the impression than an overdose of waste products, whether of one's own or other people's, must generally interfere with the metabolism of nerve tissue. Women as they grow older are apt to live much indoors. I believe the fat, flabby, paunchy woman, whether purple or pale, with feeble, irritable heart and "inadequate" kidneys, is usually the victim of rebreathed air. A "close" room will infallibly give me an abdominal distention and borborygmi within half an hour, and I am inclined to think the purity of the air breathed by the dyspeptic quite as important as his regimen or his teeth. It must, I think, sooner or later be recognized that many of the increasing ills which it has been the fashion to charge on the "hurry and brain fag" incidental to a high state of civilisation and a large population are in reality due to the greater contamination of the air we breathe by the waste products of that population, and that toxines excreted by the lungs will in time take high rank among these as both potent and insidious. If this should come to pass, the present ideas anent ventilation must be abandoned as utterly futile, and the need will be felt, not of letting a little air in, but of letting waste products out.
The Utilization of Wave Power.—The utilization of the energy which goes to waste in the movement of water, in waves, tides, and waterfalls, has been a much-studied problem during recent years. The only one of these three phenomena which has as yet been at all extensively commercially harnessed is the waterfall. There have, however, been a number of wave and tide motors constructed. The most recent and perhaps the most promising of these is the type invented by Mr. Morley Fletcher, of Westminster, England. He has made a special study of the problem of motion of the sea, and has already successfully constructed a hydraulic pump, an electric motor, and a self contained siren buoy in which the energy is obtained entirely from wave motion. The great possibilities in this direction for cheap and efficient power plants have not been appreciated by seacoast towns, but it is stated in Industries and Iron, from which we have taken the above particulars, that Mr. Fletcher is at present devoting his attention to devising schemes and designing apparatus for pumping sea water for shore purposes, ore washing, driving electric machinery for town lighting and power plants, buoys for marking harbors with beacons and fog horns, and the many other purposes to which such a constant and inexhaustible source of energy is applicable.
Dispersal of Seeds.—Having described in the Plant World some of the provisions of Nature for the dispersal of seeds, Prof. W. J. Beal adds that these various devices, besides serving to extend and multiply the species and promote its plantation on favorable soil, enable plants to flee from too great crowding of their own kind and from their plant rivals and parasites. "The adventurers among plants often meet with the best success, not because the seeds are larger or stronger or better, but because they find for a time more congenial surroundings. Our weeds, for instance, are carried for long distances by man and by him are planted in new ground that has been well prepared. Every horticulturist knows that apples grown in a new country, if suitable for apples, are fair and healthy, but the sea!) and codling moth and bitter rot and bark louse sooner or later arrive, each to begin its peculiar mode of warfare." So with peach trees and plums and their enemies. The surest way to grow a few cabbages, radishes, squashes, cucumbers, and potatoes is