Page:Natural History, Fishes.djvu/227

Rh diameters, the former is seen to be a layer of loose membranous cells of an orange colour, in what are properly called the Gold-fishes, and whitish or pellucid, in the Silver-fishes. If we now add a minute drop of water to the mass, and gently agitate it with the point of a needle, and again submit it to the microscope, we shall have a beautiful and interesting spectacle. The water around the mass is seen to be full of an infinite number of flat spiculæ or crystals, varying much in size, but of very constant form, a flat oblong prism with angular ends, as represented in the accompanying engraving. By transmitted light they are so transparent and filmy as to be only just discernible; but by reflected light, and especially under the sun’s rays, they flash like plates of polished steel. But what appears most singular, is that each spicula is perpetually vibrating and quivering with a motion apparently quite spontaneous, but probably to be referred to slight vibrations of the water in which they float; and each independently of the rest, so as to convey the impression to the observer that each is animated with life, though the scale be taken from a fish some days dead. Owing to this irregular motion, and consequent change of position, each spicula, as it assumes or leaves the reflecting angle, is momentarily brightening or waning, flashing out, or retiring into darkness, producing a magic effect on the admiring observer. To this property, we