56 CONSCIOUS NERVOUS OPERATIONS 



ful skill can be procured. A sprain, which is a sudden 

 wrenching or straining of the ligaments not sufficient to 

 dislocate the joint, is often as serious as a dislocation. 

 Neither should be neglected or treated lightly. Inflamma- 

 tion, if not checked, sometimes results in the destruction 

 of the synovial fluid and the coverings of the ends of the 

 bones in the joints, and consequently in permanent stiff- 

 ness of the joint. Immediate and long-continued rest is 

 imperative, and competent surgical advice should usually 

 be secured. 



DEMONSTRATIONS AND EXPERIMENTS 



10. The Skeleton. For the study of the osseous system there should 

 be accessible to the student a mounted human skeleton. In absence 

 of this, a mounted skeleton of a cat or dog may be used. Where the 

 school property does not include a skeleton of any kind, the enthusi- 

 astic teacher will provide one. This can be very quickly done as fol- 

 lows. Clean most of the flesh from the skeleton of a cat, dog, or 

 rabbit ; boil the partly cleaned skeleton in " liquid soap," one part, 

 and water, four parts, for forty minutes, then for thirty minutes in 

 liquid soap and water, equal parts ; cool the skeleton in cold water ; 

 clean with a brush and allow to dry. The liquid soap is made by 

 dissolving 12 grams of saltpeter and 75 grams of white soap in a mix- 

 ture of 2000 cubic centimeters of water and 150 cubic centimeters of 

 strong ammonia. 



The skeleton may be studied without any attempt at mounting it. 

 The student should follow the text of this chapter, identifying each 

 bone as it is described. The teacher will find it profitable to have each 

 student " demonstrate " the whole or a certain part of the skeleton, 

 i.e. point out and name the various parts without any reference to the 

 text and without leading questions from the teacher. 



11. Cartilage. At a meat market, bones can be procured which 

 will show hyaline cartilage on their articular surfaces. At a slaughter- 

 house can be obtained the windpipe, ears, costal cartilages, etc., of 

 various animals, and the general appearance and purposes of the dif- 

 ferent varieties of cartilage can be shown from them. To show the 



