Page:Cellular pathology as based upon physiological and pathological histology.djvu/54

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LECTURE I.

In the following preparation — a piece of costal cartilage, in a state of morbid growth — changes are evident even to the naked eye, namely, little protuberances upon FlG 9 the surface of the cartilage. Corresponding to these the microscope shows a proliferation of cartilage-cells, and we find the same forms as in the vegetable cells ; large groups of cellular elements, each of which has proceeded from a single previously existing cell, arranged in several rows, and differing from proliferating vegetable cells only in this — that there is intercellular substance between the individual groups. In the cells we can as before distinguish the external capsule, which, indeed, in the case of many cells, is composed of two, three, or more layers, and within them only does the real cell come with its membrane, contents, nucleus, and nucleolus.

In the following object you see the young ova of a frog, before the secretion of the yolk-granules has begun. The very large ovum (Eizelle) (Fig. 10, C) contains a nucleus likewise very large, in which a number of little vesicles are dispersed — and tolerably thick, opaque contents, beginning, at a certain spot, to become granular and brown. Around the cell may be remarked the relatively thin, connective tissue of the Graafian vesicle, with a hardly visible layer of epithelium. In the neigh-

rig. 9. Proliferation of cartilage ; from the costal cartilage of an adult. Large groups of cartilage-cells within a common envelope (wrongly so-called parent-cells), produced from single cells by successive subdivisions. At the edge, one of these groups has been cut through, and in it is seen a cartilage-cell invested by a number of capsular layers (external secreted masses). 300 diameters.