PRESERVATION OF SOFT FARTS. Ill 



Ether is expensive, but the use of it for removing grease from bones does not injure 

 it for anaesthetizing animals. It is said to render bones brittle. 



As turpentine, benzine, and ether are very volatile, they must be kept in tight vessels. 

 The preserving jars (Fig. 32) answer very well for the bones and either of these agents. 



Either of the three preceding methods may be employed for removing grease from 

 natural skeletons. The following method is also good for that purpose, but not quite so 

 safe, as there is some danger of loosening the ligaments. 



D. Soaking the bones in liquid soap. Place the "bones in a dish, 

 of liquid soap (§ 248) and let them remain for three or four days, in 

 some cases longer, then wash them vqyj thoroughly with clean 

 water. Dry them and expose them to the sun (§ 256). It is not 

 usually necessary to treat bones that have been prepared by the 

 liquid soap process, but bones that have been macerated or pre- 

 pared by insects may be relieved of their grease in this way. It 

 may be desirable to mix the liquid soap with an equal amount of 

 water and boil for half an hour or more. 



Peroxide of hydrogen has been found the safest and most rapid 

 agent for bleaching bones. A so-called 12 vol. per cent, solution is 

 mixed with an equal volume of water, and rendered neutral or 

 slightly alkaline by the addition of ammonia or carbonate of soda. 

 The thoroughly dried and degreased bones are placed in this in a 

 closed vessel like a preserving jar (§ 313). The bleaching is usually 

 sufficient in two to five days. 



It is necessary to keep the peroxide tightly corked and in a cool 

 place to prevent deterioration. 



THE PRESERVATION OF SOFT PARTS. 



§ 257. Practically, a bone once properly cleaned is imperisha- 

 ble, and needs only to be protected from dust or injury. But all 

 the soft parts of the body are more or less prone to decompose at 

 common temperatures and under ordinary conditions ; even when 

 treated with preservatives, they are liable to deteriorate unless con- 

 stantly cared for. 



Many agents have been employed for the delay or prevention of decomposition, and 

 for the permanent preparation of soft parts. Personal experience enables us to speak con- 

 fidently of only three — cold, arseniate of soda, and alcoliol. 



A few other agents — Irine, methyl alcohol, chloral and WicTcersheimer's liquid — will be 

 briefly mentioned. 



§ 358. Cold. — Decomposition is prevented by a temperature of C. (33 F. ), and is 

 more or leas retarded at temperatures between and 10. 



Cold may be employed alone for freezing specimens so as to keep indefinitely ; more 



