THE POPULAR SCIENCE MONTHLY.
and accurate perception of an object is gained by bringing it into all its possible relations with our different senses, and so receiving into the idea of it all the impressions which it was fitted to produce upon them—it will appear plainly how necessary to true perception, and to sound thought, which is founded on true perception, and to wise conduct, which is founded on sound thought, are thoroughness and sincerity of observation. So to observe Nature as to learn her laws and to obey them, is to observe the commandments of the Lord to do them. Speculative meditations and solitary broodings are the fruitful nurse of delusions and illusions. By faithfully intending the mind to the realities of Nature, as Bacon has it, and by living and working among men in a healthy, sympathetic way, exaggeration of a particular line of thought or feeling is prevented, and the balance of the faculties best preserved. Notably the best rules for the conduct of life are the fruits of the best observations of men and things; the achievements of science are no more than the organized gains—orderly and methodically arranged—of an exact and systematic observation of the various departments of Nature; the noblest products of the arts are Nature ennobled through human means, the art itself being Nature. There are not two worlds—a world of Nature and a world of human nature—standing over against one another in a sort of antagonism, but one world of Nature, in the orderly evolution of which human nature has its subordinate part. Delusions and hallucinations may be described as discordant notes in the grand harmony. It should, then, be every man's steadfast aim, as a part of Nature, his patient work, to cultivate such entire sincerity of relations with it, so to think, feel, and act, always in intimate unison with it, to be so completely one with it in life, that when the summons comes to surrender his mortal part to absorption into it, he does so, not fearfully, as to an enemy who has vanquished him, but trustfully, as to a mother who, when the day's task is done, bids him lie down to sleep.—Fortnightly Review.
By ROGER S. TRACY, M. D.
AN attack of yellow fever is generally quite sudden, though in some cases there are slight premonitory symptoms, such as loss of appetite, general uneasiness, headache, or costiveness. It is commonly ushered in by chilliness, alternating with flushes of heat, or the person may be overcome with languor and extreme debility, while at his usual occupation. These feelings are soon followed by fever, and the bodily temperature rises rapidly, often reaching 1022° Fahr. in a few hours, the normal temperature being 98.4°. The fever is accom-