110 ANATOMICAL TECHNOLOGY. 



skulls should be treated as just described, but they need not be 

 boiled. 



255. Bleaching Bones. In order that bones should be white 

 and clean, it is necessary that they be relieved of all their grease 

 and blood. Neither of these ends is accomplished when the flesh is 

 removed by insects ants or Dermestes. Both are fairly well accom- 

 plished by proper maceration ; and both still better by the liquid 

 soap process. 



The old method, and the one still largely employed in whitening 

 bones, is to place them where they are constantly exposed to the 

 action of the sun, rain and dew. The following methods are, how- 

 ever, more speedy and satisfactory : 



The blood is usually got rid of in the process of boiling or macer- 

 ation. If, however, one wishes to prepare bones in the best possible 

 manner, the entire vascular system may be washed out with normal 

 salt solution. To do this, insert a canula into the arch of the 

 aorta (Fig. 101) ; open the prsecava (Fig. 101) just peripherad of the 

 heart, and then, with a syringe, inject salt solution into the aorta 

 until it runs uncolored from the prsecava. See also p. 111. 



256. Freeing Bones from Grease. There are four ways of 

 removing grease from bones : 



A. By suspending them in spirits of turpentine Oleum terebin- 

 thinse rectificatum (ordinary commercial oil of turpentine will do), 

 for three or four weeks. An indefinite soaking in turpentine will 

 do no harm if the bones are suspended, and more than four weeks 

 may be necessary for large bones. 



The turpentine should be very fluid. 



The bones must be suspended so that the thick, oily substance 

 that settles to the bottom of the vessel cannot touch them. 



After the bones have soaked for a sufficient time in the turpen- 

 tine, they should be exposed to sunlight but not to rain. 



B. Suspension in benzine (common commercial benzine will do 

 very well). The bones should be treated as directed for turpentine. 



C. Soaking the bones in sulphuric ether. The bones need not 

 be suspended, simply placing them in the vessel with the ether will 

 be sufficient. The ether dissolves the grease very quickly, so that 

 small bones like those of the cat are entirely freed from grease in a 

 fortnight or even a less time. The bones should be exposed to light 

 as directed above. 



