. Evenings at the microscope : or, researches among the minuter organs and forms of animal life. Microscopy; Microscopes; Medical microscopy. lIAntS, FEATHKKS, AND SCALES. 23. BOALE OP FIOCNDEE. a. J^atural size. from the Flounder, which, being coarsely lined, shows the structure well; or in these from the Green "Wrasse. I will now apply to one of these a power of 600 di- ameters, concentrating the light thrown through the scale from the mirror by the achromatic condenser, and examine the scale anew. You now see two distinct layers ; the upper one which bears the con- centric lines, and a
. Evenings at the microscope : or, researches among the minuter organs and forms of animal life. Microscopy; Microscopes; Medical microscopy. lIAntS, FEATHKKS, AND SCALES. 23. BOALE OP FIOCNDEE. a. J^atural size. from the Flounder, which, being coarsely lined, shows the structure well; or in these from the Green "Wrasse. I will now apply to one of these a power of 600 di- ameters, concentrating the light thrown through the scale from the mirror by the achromatic condenser, and examine the scale anew. You now see two distinct layers ; the upper one which bears the con- centric lines, and a lower clear one which not only fills the radiating bands, but underlies the whole of the lined parts. The con- centric lines of the upper layer do not now appear to be edges of successive plates, but irregular canals running through the solid substance. This, however, is illusory: . for, by delicate focussing, we perceive that each portion marked by these lines is really in a difierent plane from the others, tliat the highest is at the centre of radiation of the scale, and that each is successively lower till we reach the margin. But now, if with very sharp scissors we cut one of these scales longitudinally through the centre, and examine the cut edge, we find that each of these lines forms a distinct ridge. On the other hand, the under layer of clear substance is quite smooth, and always a little exceeds the margin of the concentrically lined portion. The clear substance that fills the radiat- ing slits agrees both in texture and level with this lower layer, and is manifestly continuous with it. Hence, I think that, in these slit scales, the upper layer is formed, as commonly believed, by successive. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Gosse, Philip Henry, 1810-1888. New York, D. Appleton
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