Knowing what is now known of the efficacy of light in curing certain affections, especially the violet and blue light, is it too early to suggest that much of the power of quinine is due to the body being saturated with this "colorless" dye and so cutting off light which the constituents of the body are not strong enough to bear without their balancing power being impaired, and so leaving the battlefield at the mercy of inimical fever forces? Tropical travelers are warned not so much to use quinine after attack, but to saturate the body (with minute doses) commencing several days before entering the dangerous zone. In spite of endless fraud and humbug and "fake" photography, it has long been suspected that the invisible can be photographed. As shown, we have never been doing anything else in our photography except photographing much of the invisible. Without saying that it has or has not been done, we may well ask if it is really so difficult to imagine that much of what inhabits the "seeming void" may be made visible to the lunar surface of the plate? Professor Wood's experiments on the lines of photography by invisible rays are of absorbing interest. Not only has he made interesting photographs of objects by means of the invisible violet rays, but also by means of the invisible rays below the red end of the spectrum. And he shows one very interesting result of photographing Chinese white by these ultra-violet rays--as though the pigment were a pure black! This illustrates the fact long known to photo-engravers' artists that Chinese white is a bad white to use except in a mixed tint. The Chinese white cuts off so much of this invisible chemically-active "white" as to appear gray even to an ordinary plate's "lunar eye." Another startling result is that by the ultra-violet light a man's shadow may entirely disappear when he is photographed in sunlight. One wonders if the strange Eastern "superstitions" as to shadows and men without shadows do not have a real scientific basis. Perhaps R. L. Stevenson's little child who rose so early that his "naughty little shadow had stayed at home ... and was fast asleep in bed," could tell us. HEREDITY AND BIOLOGY: by H. T. Edge, B. A. (Cantab.) The word "heredity" is one that is much conjured with nowadays, so that it is important to understand its meaning and import. In so far as its meaning covers facts ascertained by reliable observation, and correct inferences therefrom, we must be prepared to accord the word the respect which in that case it deserves; but in so far as it may stand for imperfect observations and the faulty theories inferred therefrom, we must be equally prepared to apply scrutiny and reserve.