the microscope and iiow to use it. 239 



Embedding Mixtures. 



(^7) White wax or olive oil, equal parts ; melted and well 



mixed. This mass may be varied in consistency by diminishing 



the olive oil used. 



(/^) Spermaceti and Castor Oil.— Four parts of spermaceti and 

 one part of castor oil. 



(c) Cocoa Butter may be used alone, or combined with paraffin 

 wax, or spermaceti and paraffin. 



(d) Paraffin and Lard. — Take 5 parts (by weight) of solid 

 paraffin and one of hog's lard and of paraffin oil ; melt at a gentle 

 heat, and mix thoroughly. 



(f) Paraffin and Vaseline. — Two parts solid paraffin mixed 

 with one of vaseline makes a transparent mass. 



(/J Glycerine and Tragacanth.— Take two drms. of glycerine 

 and mix with i| drms. of powdered gum tragacanth. The tissue 

 is cut and placed in a pill-box, and the mixture poured in. If the 

 specimen is to be preserved for a longer time, the bottom of the 

 box may be taken off and the side slit up. The specimen will be 

 embedded in a solid elastic cake, and may be slipped into alcohol 

 until required. When it is to be kept in spirits less than 24 hours, 

 the mixture should be glycerine, 2 drms. ; tragacanth (powdered), 

 9 drs. ; gum arable, 15 grs. Tissues that have lain in spirit should 

 be steeped in cold water for a few hours before embedding. 



The embedding mixtures may be arranged as follows : — 



Solid paraffin, 3 parts ; Cocoa Butter, i part ; Hog's Lard, 

 3 parts. Soft. 



Solid Paraffin, 3 parts ; Cocoa Butter, 2 parts ; Spermaceti, 

 I part. Hard. 



Solid Paraffin, 3 parts ; Cocoa Butter, i part ; Spermaceti, 

 I part. Harder. 



Paraffin, 2 parts ; Vaseline, i part. Transparent and easy to 

 cut. 



These are very common mixtures for embedding, although 

 Mr. Cole recommends them only to " those wlio are fond of 

 messes, and the method is mentioned only to condemn it as 

 unnecessary and dirty in every way." Notwithstanding this ter- 

 rible denunciation, this method will continue to occupy its position 



