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THEORY AND PRACTICE OF MEDICINE.
finally separating- altog-ether. This process is due to the power which these corpuscles possess, by virtue of their amoeboid nature, of spontaneous movement, as well as of altering in shape and digesting- the protoplasm of the vascular walls, so that no actual openings are left in the vessels to indicate the points at which they have escaped. The liberated white corpuscles are named leucocytes, and after they leave the vessels they send
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out processes, assume peculiar shapes, and migrate far and wide into the surrounding tissues, at the same time often undergoing a process of division, and thus becoming in- creased in number. The red corpuscles ex- hibit the same tendency to aggregation and Ameboid stasis, and they may adhere to each other so '"Reckh^ghTu^en)'. closely that their outlines are quite obscured.
They also migrate through the walls of the vessels, chiefly the capillaries, but not nearly to the same extent as the white blood- cells. In an inflamed area no migration occurs in the centre, where there is stasis ; around this both white and red corpuscles escape ; but in the outer circle only white corpuscles migrate. Dr. Lionel Beale affirms that in inflammation minute particles of bioplasm or germinal matter of the blood pass through small rents or fissures in the capillary walls, and afterwards grow and multiply by divi- sion. Some of these particles, he says, are detached from white corpuscles. He considers that most of the particles seen outside the vessels originate in this way, and not from the direct transit of white corpuscles.
Another phenomenon which almost invariably occurs is the exu- dalion of the liquid portion of the blood out of the vessels into the surrounding tissues. Though usually called liquor sanguinis, the exuded liquid is rarely identical with this fluid in its composition. It may be mere serum, but as a rule contains fibrinogenous materials, as well as albumen, and also a considerable proportion of phos- phates, chlorides, and carbonates. Its nature and quantity will vary much according to the seat and intensity of the inflammation as will be more fully pointed out further on.
The alterations thus far described cannot of course be observed in structures which have no vessels, such as cartilage ; but they may then be noticed in the vessels of neighbouring tissues, from which the nutriment which supplies the non-vascular structures is derived.
B, Changes in the affected tissues. — The nutritive process in the in- flamed tissues themselves becomes speedily disturbed, but this takes place to different degrees in diff"erent tissues, and in some struc- tures it is the only perceptible deviation from health, there being no appreciable amount of exudation from the vessels, and little or no migration of corpuscles. Such inflammations are named parejt- chymatous, and are observed in connection with cartilages and certain organs, such as the kidneys.
In the earlier period of inflammation the change which the affected tissue presents is an increase in the nutritive activity of certain
