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the natives before exportation. When first introduced here and 

 into England, much bad material was obtained. Some samples 

 were found to be acid, and lime was recommended for its neu- 

 tralization. This remedy however soon became an abuse, for 

 lime and oxide of zinc were at one time extensively used for its 

 adulteration, no less than fifty per cent, of lime being often 

 introduced. Mr. Stodder has specimens of the pure gum, man- 

 ufactured into different articles several years since, now in good 

 condition. 



Mr. C. C. Sheafe said he had a pipe, connected with bellows 

 and freely suspended in the air, which had been in use about 

 eight months, and which was now as fragile as glass. 



Dr. N. C. Keep stated that he had used small quantities of 

 Gutta Percha for several years. He had observed that when 

 allowed to rest untouched for a considerable length of time, it 

 uniformly lost its tenacity ; but on being worked over again with 

 the aid of heat, it appeared as tough and good as at first. The 

 simple process of heating is not sufficient for this purpose, but 

 the material should be re- wrought. The greatest nicety is 

 required in determining the proper degree of heat, as brittleness 

 may be occasioned by overheating. The use which he had 

 made of it was in dental operations, principally as a temporary 

 filling in sensitive cavities, etc. 



Dr. S. L. Abbot stated that Gutta Percha had been used with 

 success at the Massachusetts General Hospital, at the suggestion 

 of Dr. H. J. Bigelovv, to take impressions of strictures ; but 

 other instances have occurred where this material failed for this 

 purpose and had even given rise to serious trouble from the 

 breaking of the instrument. 



Dr. C. D, Homans said that the same material was much 

 used at the hospital for splints, it being simply remoulded in each 

 case. 



Dr. Calvin G. Page remarked that brittleness had been 

 observed in thick sheets, which had lain unused for some time 

 in the hospital,, but these were afterwards re- worked and put 

 into use. 



Dr. Chas. T. Jackson stated that Gutta Percha varied very 

 much in quality in different specimens. He had noticed this 



