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

upon to destroy a tooth-pulp. The nature of the apparatus which he employs for this purpose is thus described: The bat- tery is what is termed compound, i. e., consisting of six pairs of large plates, the one of zinc covered with quicksilver, and the other a platinized silver, which are contained in six cells, or gallon jars of crockery or glass, (called Smee's battery,) which are set in action by one fluid, viz., dilute sulphuric acid. The battery may of course vary according to the choice and taste of the operator ; but it is desirable to render it as elegant and as simple in arrangement as possible. When I first employed the electric cautery, I used a battery of two (large) pairs of plates in a single cell. I now prefer the larger battery, of six cells, because a large battery, with weak acid, will run longer than a small (or single cell) battery, with strong acid; besides this, the action of the battery is more uniform, and lasts much longer. A Smee's battery is the best for dental purposes. It is always clean, ready any instant when wanted, and has the advantage, moreover, of cheapness. Grove's battery is not so adapted to these purposes, because it is troublesome, and often gives out fumes of nitrous acid, which is decidedly objectionable. There is none of this trouble from a Smee's battery. Dr. Braithewaite, in his " Retrospect," Part 36, page 296, makes some capital extracts out of the Quarterly Journal of Dental Science, from the pen of Dr. Underwood, on the " Treat- ment of the Exposed and Diseased Dental Pulp." The writer there says much in these words : The parts of the teeth possess- ing nervous sensibility are the pulp, or, as it is more generally termed, the "nerve," as also the periosteum and the fine mem- brane situated between the enamel and the bone. Mr. Tomes considers the sensibility of this part of the tooth to be owing to the nerve fibrils in the dentinal tubes. He says the greater degree of sensitiveness observable in the dentine, immediately below the enamel, that is, at the point of ultimate distribution of the dental tubes, and consequently of the nerve fibrils, may be fully accounted for on the supposition that the latter are organs of sensation. No doubt the nervous filaments passing through the tubidi, 51