278 ANNUAL OF SCIENTIFIC DISCOVERT. 



hardness, suppleness, or transparency. This substance may replace, in 

 many cases, plaster, marble, ivory, horn, bone, gutta-percha, gelantine, etc. 



ON A METHOD OF IMPARTING A RED COLOR TO BONE AND IVORY. 



BY DR. J. C. KELLERMANN. 



The bone to be colored is laid for fifteen to twenty minutes in very dilute 

 cold nitric acid of the strength of a good vinegar; this dilute nitric acid is 

 obtained by mixing fully one-half a litre of soft water with about thirteen 

 grms. of nitric acid. The bone is then immersed for fifteen to twenty 

 minutes in a solution of protochloride of tin, made by dissolving a piece of 

 the size of a lentil in a pint of water. The objects thus mordanted are then 

 put into the following red-bath, which must first be heated until it begins to 

 boil. 



Med-bath . For an experiment on the small scale, take three to five grms. 

 of fine red carmine, pour to it ten to twelve drops of ammonia, and stir it 

 up well until the carmine is dissolved; then add about two ounces of soft 

 water. In this bath, when heated to boiling, the objects must be left for 

 about fifteen minutes. The tints obtained are more vivid when the boiling 

 of the bath is not continued whilst the objects are in it. 



If it be desired to change the tint thus obtained (a very fiery carmine-red) 

 to a more scarlet, one of the following methods may be employed. When 

 the red-bath begins to boil, and immediately after the objects have been 

 immersed in it, five to ten drops of tartaric acid, of the strength of a good 

 vinegar, may be added; or the water in which the protochloride of tin is to 

 be dissolved may be mixed with an extremely small quantity of English 

 sulphuric acid. Dingier' s Polytechn. Journal. 



ON THE TREPANATION OF SOME SIMPLE CEMENTS. 



Dr. Davy, F. R. S., has recently published the following paper on the 

 manufacture of various simple cements, which admit of a useful and ready 

 application. 



Gutta-percha, as is well known, is itself an admirable cement for certain 

 purposes, when softened by hot water or by a moderate degree of heat; and 

 it has been used in making other cements ; but I am not aware of any cement 

 described in which it forms a part ; its high commercial value is an obstacle 

 to its application in many cases where it could be employed with advantage. 



Gutta-percha, though readily adapted to an almost endless variety of uses, 

 is, however, not easily rendered fluid when alone, and hence is not quite 

 manageable enough for certain purposes. 



I have made many experiments, using different proportions of gutta-per- 

 cha with pitch, resin, wax, etc., with a view to form useful cements. In the 

 present communication I propose to notice only one cement, which I made 

 by melting in an iron saucepan. Two parts by weight of common pitch, 

 and adding to it one part by weight of gutta-percha, stirring and mixing 

 them well together until they were completely incorporated with or united 

 with each other, formed a homogeneous fluid, which may be used in this 

 state for many purposes ; but which, on account of the facility and tenacity 

 with which it adheres to metals, stones, glass, etc., I found convenient to 

 pour into a large basin of cold water, in a thinner or thicker stream, or as ti 



