Volume 1

Lectures on histology : delivered at the Royal College of Surgeons of England / by John Quekett.

Date:
1852-1854
Catalogue details

Licence: Public Domain Mark

Credit: Lectures on histology : delivered at the Royal College of Surgeons of England / by John Quekett. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    gous vegetable forms, of simple cells; but the progress of development in animals is much more rapid than in plants, producing a greater variety of external form and complexity of structure among groups which would otherwise hold a parallel position in the two kingdoms. One great distinction between the elementary tissues of plants and animals, which should he always kept in view by the student is, that while in the plant the cell, however modified in form, still possesses all the characters of a cell; in the animal it usually under- goes a development into tissues, in which the cellular form completely disappears, and the cellular origin of the tissue can only be discovered by studying it in its embryonic condition. MEMBRANE. It is now generally considered by vegetable phy- siologists that, with the addition of an intercellular mucus or cambium, all plants are made up of a mem- brane existing in the form of cells or utricles, having as an organic basis a tough insoluble material called cellulose. Membrane, therefore, is regarded as the sole element of plants. Some years since, fibre was also enumerated as an element, but more recent obser- vation has shown that this is always subsequently deposited on the inner surface of membrane.