The Dental cosmos . , except at the outermost part, which isfilled out with cement. A careful examination of the preparationshows that the wall, at the time of the wound, could not have beenover one-third of an inch thick. A longitudinal section of a beautiful preparation of this class is illus-trated in Fig. 30. An iron ball breaks through the wall of the toothat a, where it is a little over three-eighths of an inch thick. The exactthickness may be seen at b. Fragments of the broken wall are forced 516 THE DENTAL COSMOS. into the pulp, while the ball penetrates three inches into the pulp be-f
The Dental cosmos . , except at the outermost part, which isfilled out with cement. A careful examination of the preparationshows that the wall, at the time of the wound, could not have beenover one-third of an inch thick. A longitudinal section of a beautiful preparation of this class is illus-trated in Fig. 30. An iron ball breaks through the wall of the toothat a, where it is a little over three-eighths of an inch thick. The exactthickness may be seen at b. Fragments of the broken wall are forced 516 THE DENTAL COSMOS. into the pulp, while the ball penetrates three inches into the pulp be-fore coming to rest, where it becomes surrounded by an irregular, flat-tened mass of osteo-dentine, nearly filling up the whole pulp-chamberat that point. The fragments of the primitive wall become imbedded in osteo-dentine, while the wound is healed from without by a deposit ofcementum. The new formation in which the ball is imbedded is twoand a half inches long, two inches broad, and one and a quarter inch Fig. Fig. 30.—Part of a longitudinal section from an elephants tusk, p, pulp-chamber : b, primi-tive tooth-wall; a, entrance of ball; c, mass of irregular dentine formed around the ball, extend-ing quite across the pulp-chamber. thick. It was found in the pulp-chamber of a tusk about eight feetin length, and showed nothing on the outside indicating the presenceof a ball. Only my curiosity to see how the specimen looked insideled to the discovery of its contents. I then carefully followed thecareer of the tusk till it came into the hands of the turner, when Isucceeded in securing the portion showing the entrance of the ball, asseen in Fig. 30. An equally striking specimen of this class, in which the process of ANATOMY AND PATHOLOGY OF THE TUSKS OF THE ELEPHANT. 517 encapsulation took a somewhat different course and reached a moreadvanced stage, is illustrated in Fig. 31. Here again we have nodifficulty in determining the thickness of the walls of the tusk at thetime th
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectdentist, bookyear1890
