Crystals and Polariscope Objects 205 



hours or days, in accordance with the consistency of the 

 tissue. When soft enough, wash away the potash with 

 water, and place in methylated spirit, in which they may 

 be preserved until required. Then make transverse and 

 longitudinal sections, dehydrate in methylated spirit, clear 

 in clove-oil, and mount in Canada balsam. 



Small Fine Hairs. Cut off a number of hairs, tie them 

 up into a bundle with some cotton, and soak for a few 

 minutes in warm water. Make up a strong solution of 

 gelatine in water, and transfer the bundle of hairs to it, 

 and soak it for several hours in a hot-water bath until the 

 gelatine has penetrated to the centre of the bundle. Ee- 

 move from the gelatine on the point of a needle, and hold 

 it exposed to the air until the gelatine has cooled ; then 

 push them from off the needle into a bottle of methylated 

 spirit, and soak for an hour or two to complete the harden- 

 ing. Embed in carrot, put in a microtome, and cut 

 transverse sections, and as they are cut place them in 

 methylated spirit to dehydrate ; then clear in clove-oil, and 

 mount in Canada balsam. 



Horns, hoofs, whalebone, and claws all require steep- 

 ing in liq. potassee until soft ; they are then to be washed 

 in water, and preserved in methylated spirit until required. 

 Embed in carrot, place in a well microtome, make trans- 

 verse and longitudinal sections, dehydrate in methylated 

 spirit, clear in clove- oil, and mount in Canada balsam. 



Decalcified Bones (see Lesson I.). Embed in carrot, 

 make transverse and longitudinal sections, dehydrate in 

 methylated spirit, clear in clove-oil, and mount in Canada 

 balsam. 



Muscular Fibres. Take the tongue of a cat, harden 

 it in methylated spirit for a week or ten days ; then 

 embed in carrot, and make transverse or longitudinal sec- 

 tions, dehydrate, clear in clove-oil, and mount in Canada 

 balsam. 



