Page:The Zoologist, 4th series, vol 6 (1902).djvu/205

Rh kind of secretion is that of strong scented ethereal oils. Species of Artemisia are characteristic plants of the deserts of Africa and Beluchistan; Pulicaria arabica has a particularly powerful odour. "Since Dr. Tyndall has shown how minute quantities of such oils diffused through the air are capable of arresting radiant heat, it has been suggested that this is one of the many resources to which desert plants appeal, in order to reduce the ill-effects of the heated atmosphere which surrounds them; and, just as the presence and quantity of opium, hasheesh, aconitine, &c, secreted by plants vary greatly with the climate, so it is reasonable, in the absence of strict investigations, to assume that these oils are in an excess through the intense heat and other conditions of the climate of deserts." This appears to have been first suggested by Dr. Volkens, and Mr. Henslow would further apply the suggestion to odoriferous plants growing at high altitudes. These observations or suggestions cannot, of course, have any application beyond the areas mentioned, and, if correct, tend to prove that scents emitted by plants may have other purposes besides those of animal attraction, and again inculcate the necessary caution against concluding that a quality many times observed to have an attractive purpose is necessarily fulfilling that function in all cases. The exhaustive and eloquent summing up of a brilliant judge may excite the admiration of the lounger in court, but does not necessarily have that effect on the litigant whose case it demolishes. Because a plant exhales an offensive odour, it is not less attractive to some insects. In Borneo, Mr. Burbidge found a large amorphophallus bearing fetid flowers; on cutting one of these open he found its basin "half-full of ants of two kinds, and numerous small black coleoptera were running about in the spathe."

The appreciation of scents and odours by mankind is not of universal similiaritysimilarity [sic], but varied and capable of artificial distortion. The sense of smell is generally considered as more highly developed in savage than in civilized races. Nevertheless, as Darwin has observed, it does not "prevent the Esquimaux