Electro-physiology and electro-therapeutics : showing the best methods for the medical uses of electricity / By Alfred C. Garratt.

Now, the difference between what is called vascular and non- vascular tissues (to which latter division articular cartilages be- long) is known to be so slight, that the method by which this structure is nourished is no longer doubtful. The blood being conducted to every tissue by its ordinary vessels, each tissue extracts, or rather imbibes, the material requisite for its own best nourishment; the only difference between the vascular and non- vascular parts being determined by the space through which this process of imbibition takes place; in the latter, the vessels do not perforate its substance. The nucleated cells, however, through which all the living structures are formed, and grow, still do absorb from the vessels, however distant, their quantum of nourishment; and in articular cartilages, these cells are as active as in any other tissues. The method by which these blood vessels supply the articular cartilages may be thus briefly described, the necessity to un- derstand their vascular supply being evident when their pa- thology is looked into. That the principal source of supply is derived through their bony attachment, the researches of Birkett, Toynbee, and others have full well demonstrated. The vessels at their bony base form loops, and yield the required nourishment " somewhat in the same way as the epidermis scales are nourished upon the vascular loops of the coriuin." The vessels ramifying into the synovial membrane furnish, at their circumference-, to their adjacent surfaces the sufficient supply. It is clear, then, that structures deriving their nourishment through other adjacent tissues must depend much upon the integrity of these tissues ; and here such an example is witnessed, particularly in old people. Articular cartilages are liable to diseases which may all be classed as the enlarged or hypertro- phied, or atrophied, that is, wasted. They are peculiarly liable to granular, fatty, and fibrous degeneration, but not to inflamma- tion. Now, all these seem to arise either from perversion of nutrition, or else diminished or arrested nutrition, but never through excessive vascular supply, or through single excess of function. Hence the reasonableness of electric currents, prop- erly applied, being of the greatest service, in all such joint affec- 31