perilous to give them a first look of the public. They are formidable simply as the earliest popularizers of some interesting science, or the first promulgators of some class of curious little-known facts, with which they mix up their special contributions of error,--often the only portion of their writings that really belongs to themselves. Nor is it at all so easy to _counteract_ as to _confute_ them. A masterly confutation of the part of their works truly their own may, from its subject, be a very unreadable book: it can have but the insinuated poison to deal with, unmixed with the palatable pabulum in which the poison has been conveyed; and mere treatises on poisons, whether moral or medical, are rarely works of a very delectable order. It seems to be on this principle that there exists no confutation of the "Constitution of Man" in which the ordinary reader finds amusement to carry him through; whereas the work itself, full of curious miscellaneous information, is eminently readable; and that the "Vestiges of Creation,"--a treatise as entertaining as the "Arabian Nights,"--bids fair, not from the amount of error which it contains, but from the amount of fresh and interestingly told truth with which the error is mingled, to live and do mischief when the various solidly-scientific replies which it has called forth are laid upon the shelf. Both the "Constitution" and the "Vestiges" had the advantage, so essential to the basilisk, of taking the first glance of the public on their respective subjects; whereas their confutators have been able to render them back but mere _return_ glances. The only efficiently counteractive mode of looking down the danger, in cases of this kind, is the mode adopted by Mr. Longmuir.