CHAPTER VI. 



LABORATORY WORK. 



THE account which follows is from the necessities of the 

 case greatly condensed, many points of great importance be- 

 ing entirely omitted. This account is intended for the 

 beginner only. For more extended directions the student 

 is directed to the list of books at the end of this chapter ; 

 those of Huxley and Martin, Tulk and Henfrey, Burden- 

 Sanderson, Strieker and Ranvier giving the best and most 

 detailed instructions. Beale's book, like most of his other 

 works, is in many respects unreliable. 



DISSECTING. 



All small objects should be dissected under water or a 

 mixture of alcohol and water, as these media tend to support 

 and float the parts and tissues which otherwise would mat to- 

 gether to a greater or less extent, and thus obscure the dis- 

 section. Dissecting troughs are used for this purpose. 

 These are usually made of tin (firj. 36). These troughs, for 

 ordinary work, should be about six by eight inches square, 

 and one and a half to two inches in depth. Small tin slips 



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