LIST OF KEAGBNTS, ETC. 



381 



4. Alcoholic Carminic Acid. 



JJse. — Stains rapidly the protoplasm and nuclei of fresh or 



alcoholic specimens. 

 Preparation. — The crystals of carminic acid come in small 



vials. A sufficient number of the crystals may be added 



to alcohol of any strength until a solution of the desired 



depth of color has been produced. 



5. Barium Hydrate. 



JJse. — The solutions of barium hydrate are used to detect 

 the presence of carbon dioxide, which unites with the 

 barium hydrate and forms' a white precipitate of barium 

 carbonate. 



Preparation. — Add barium oxide to distilled water until a 

 saturated solution is formed. 



6. Bristles. 



These are used to insert into and follow the course of 

 blood-vessels, ducts, etc. Their ends should be guarded 

 by a small knob of sealing-wax. It is convenient to 

 have bristles of various lengths, colors, and degrees of 

 stiffness. They may be obtained from manufacturers of 

 paint-brushes. 



7. Chloral Hydrate. 



Use. — Anaesthetic and antiseptic ; clears pollen-grains, etc. 



Preparation. — Add two grams of the crystals to ninety- 

 eight cubic centimetres of distilled water. This solution 

 may be added drop by drop to the water containing small 

 animals which it is desired to anaesthetize. 



