Our Domestic Animals in Health and Disease. DIV (Paperback)

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1863 edition. Excerpt: ... called into existence the peculiar apparatus which the nervous matter is employed to form." The nervous system is made up of two elementary structures--cells and fibres. "The nerve-cell has been described as consisting of an envelope, granular contents, and a nucleus with one or more nucleoli. So far, there is no difference between the so-called nerve-cell and any other cell; but it is the great diversity in size, its frequent coloration with pigment, and the brilliancy of a vesicular nucleus which may be regarded as somewhat characteristic of the nervous element, which is usually stellate, round, or Fig. 208.--Multipolar nerve-cell, showing its nucleus and nucleolus. oval, and connected with fibrous prolongations. Some of the cells are as large as 3$Tth of an inch in diameter, and they are not unfrequently as small as-th. Vesicular bodies are interspersed amongst the cellular elements." "The nerve-fibres are found in the nervous centres, and in the nerves which connect the latter with the peripheral parts of the body. They are combined with, or spring from, the nerve-cells in the grey matter of all nervous ganglia. The ultimate nerve-fibres are of two kinds--tubular or white and grey or gelatinous. The white have a special envelope, in the interior of which is Remak's primitive band or axis cylinder (Purkinje), surrounded by a medullary sheath or white substance of Schwann. The tubular fibres have been called medullated by Kolliker, to distinguish them from the non-rnedullated. The latter occur in organs of special sense, when delicate plexuses are formed as in the retina, or the olfactory and auditory apparatuses, and have a structureless envelope containing a clear granular axis without the white substanca" Fig. 209.--Tubular or white...