Dr. G. V. Black, a dentistof Jacksonville, Fia. , has made some interesting experiments upon the force exerted by the human jaws in the ordinary mastication of food, and also the greatest force which the jaws are capable of exerting. By means of a spring instrument providedwith a registering device he took records of about 150 "bites" of different persons. Of these 50 have been preserved as characteristic of the ordinary man, wornan and child. The smallest pressure recorded was 30 pounds, by a little girl 7 years old. This was with the incisors. Using her molars, the same child exerted a force of 65 pounds. The highest record was made by a physician of 35. The instrument used only registered 270 pounds, and he closed it together ■without apparent effort. There was no method of determining how f ar above 270 pounds he could have gone. This test was made with the molars. Several persons exceeded a force of 100 poirads with the incisors and 200 with the molars. Thephysical condition of the persons experimented upon seemed to have little bearing upon the result. Dr. Black is of the opinión that the condition of the peridental membranes is the controlling factor, rather than muscular strength. Dr. Black found that in the habitual chewing of food much more force is exerted than is necessary.