98 TEE SEA SHORE 



dilute spirit, may be soaked in water, then transferred direct to the 

 glass slip, and covered with a drop of glycerine. Any excess of the 

 glycerine should then be absorbed from around the cover-glass by 

 means of a strip of blotting-paper, and the edge of the cover cemented 

 by gold size applied with a small camel-hair brush. 



Glycerine jelly is also a valuable mountant for permanent work. 

 When this is used the object should first be soaked in glycerine, 

 and then in the melted jelly. It is then transferred to a drop of 

 melted jelly which has been placed on a warm slide, and covered 

 as before. The jelly soon solidifies, so that a ring of cement is not 

 absolutely necessary, though it is advisable, as a rule, to cement 

 the cover-glass all round with gold size or black varnish. 



Sections cut while frozen are best mounted in glycerine, to 

 which they may be transferred direct. 



Canada balsam is one of the best media for permanent mounting ; 

 and, as it becomes very hard after a time, it serves the purposes of 

 both preservative and cement. When this is used the object must 

 be entirely freed from water by soaking it in absolute alcohol. It 

 is then put into turpentine for a minute or two, transferred to a 

 wann slide, and covered with a drop of the prepared balsam. 

 Sections that have been imbedded in paraffin may be mounted 

 in this way, the turpentine acting as a solvent for the paraffin in 

 which it was cut. 



Although the compound microscope is absolutely necessary for 

 the study of the minutest forms of life and of the minute structure 

 of the various tissues of larger beings, yet the young naturalist will 

 find that a vast amount of good work may be done without its aid. 

 Thus the general structure of the larger species may be made out 

 by means of simple dissections requiring no extraordinary skill on 

 the part of the worker, and with appliances that may be obtained 

 at a low cost. Certain of the marine animals, however, require 

 special treatment that can hardly be described in a short chapter 

 devoted to general instructions only, but hints with regards to these 

 will be given in future chapters in which the animals referred to 

 are described. 



The appliances referred to above include nothing more than a 

 simple form of dissecting trough, a few dissecting instruments, and 

 one or two minor accessories that may always be found at hand as 

 required. 



The dissection of animals is always best performed under water, 

 for by this method the object examined may not only be kept clean 



