Evenings at the microscope; or, Researches among the minuter organs and forms of animal life / by Philip Henry Gosse, F.R.S.

  • Gosse, Philip Henry, 1810-1888.
Date:
1859
Catalogue details

Licence: Public Domain Mark

Credit: Evenings at the microscope; or, Researches among the minuter organs and forms of animal life / by Philip Henry Gosse, F.R.S. Source: Wellcome Collection.

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    a cavity passing up through the hair. It is sur- rounded by a layer of cells, called medullary, and which appear black, because they are filled with air. The finer hairs of the Horse and the Ass, such as those selected from the cheeks, have the sinuous edges of the plates about as close as in human hair. But they are distinguished at once by the conspicuous- ness of the medullary portion, which is thick, and quite opaque, and is broken up (especially towards each extremity of the hair) into separate longitudinal irregular masses. The fine wool of the Sheep is clothed with imbri- cations,1 proportionally much fewer than those of human hair, while the diameter is also much less. Thus these examples, selected from fine flannel and from coarse worsted, vary in diameter from -roWth to 7 forth of an inch; and there are, upon an average, about two imbrications in a space equal to the diameter. No colour is per- ceptible in these specimens; they are as transparent and colourless as glass. The imbricated plates project here considerably more than in either of the examples we before examined; the “teeth,” however, form an obtuse angle. We shall presently see the importance FIB HE OF SIIEEP'8 A «/ X °°L- of this imbricate structure; but we will first look at a few more examples, in which we shall find it still more strongly developed, in conjunction 1 A structure is said to be imbricated when it is arranged like tiles on the roof of a house.