296 HOW TO WORK 



with it retain their colour perfectly, and the injected tissues can also 

 be stained with carmine. 



Price's glycerine, 2 oz. by measure. 



Tincture or solution of perchloride of iron,* 10 drops. 



Ferrocyanide of potassium, 3 grains. 



Strong hydrochloric acid, 3 drops. 



Water, i oz. 



Mix the tincture of iron with one ounce of the glycerine ; and the 

 ferrocyanide of potassium, first dissolved in a little water, with the 

 other ounce. These solutions are to be mixed together very gradually 

 in a bottle, and are to be well shaken during admixture. The iron 

 solution must be added to the ferrocyanide of potassium. Lastly, the 

 water and hydrochloric acid are to be added. Sometimes I add a 

 little alcohol (2 drachms) to the above mixture. 



This fluid (it is not a solution], does not deposit the slightest sedi- 

 ment, even if kept for some time, and it appears like a blue solution 

 when examined under high magnifying powers, in consequence of the 

 insoluble particles of Prussian blue being so very minute. 



If preferred, the Turnbull's blue may be used instead of Prussian 

 blue, half the quantities of the ferridcyanide of potassium and sulphate 

 of iron recommended in p. 94, being used, and the hydrochloric 

 acid may be left out. The glycerine and water in the proportions 

 just given. 



37O. Other Colouring Solutions with Glycerine. Many of the 

 staining fluids given in pp. no to 113 may be prepared with glyce- 

 rine. Thus, I dissolve nitrate of silver, the anilin colours, and many 

 others, in glycerine instead of in water. The salt should be dissolved 

 in a very little water in the first instance, and this solution added to 

 the glycerine. Indeed, all the fluids I now use for preparing speci- 

 mens contain syrup or glycerine as the basis. 



3*31. Glycerine and Water and Glycerine and Acetic Acid for 

 Washing and Preserving thin Sections. After the specimen has been 

 properly stained, small pieces are to be washed in a solution con- 

 sisting of 



Strong glycerine, 2 parts. 

 Water, i part. 



After being soaked in this for an hour or two, they may be transferred 

 to the following acid fluid : 



Strong glycerine, i ounce. 



Strong acetic acid, 5 drops. 



* The Tinctitra Ferri Perchloridi and the Liquor Ferri Perchloridi of the 

 British Pharmacopoeia of 1867, arc of the same strength, and consist of one part of 

 strong Liquor Ferri l\';\-klor to three parts by measure of spirit or water. 



