72 THE MICROSCOPIST. 



For transparent injections, gelatin may be used combined 

 with colored solutions, or still better, glycerin, which may 

 be used cold. 



Thiersch's Blue. Half an ounce of warm concentrated 

 solution (2:1) of fine gelatin is mixed with 6 cubic centim- 

 etres of a saturated solution of sulphate of iron. In 

 another vessel, 1 ounce of the gelatin solution is mixed 

 with 12 cubic centimetres of saturated solution of ferro- 

 cyanide of potassium, to which 12 cubic centimetres of 

 saturated solution of oxalic acid is added. When cold, 

 add the gelatinous solution of sulphate of iron drop by 

 drop, with constant stirring, to the other. Warm it, 

 still stirring, and filter through flannel. 



Gerlach's Carmine. Dissolve 5 grammes (77 grains) of 

 fine carmine in 4 grammes (70 grains) of water and J 

 gramme (8 drops) of liquor ammonia. Let it stand sev- 

 eral days (not airtight), and mix with a solution of 6 

 grammes of fine gelatin to 8 grammes of water, to which 

 a few drops of acetic acid are added. 



Thiersctis Yellow. Prepare a solution of chromate of 

 potash (1 : 11), and a second solution of nitrate of lead, of 

 same strength. To 1 part of the first add 4 parts of solu- 

 tion of gelatin (about 20 cubic centimetres to 80), and to 

 2 parts of the second add 4 parts of gelatin (40 cubic cen- 

 timetres to 80). Mix slowly and carefully, heat on a 

 water-bath, and filter through flannel. 



Equal parts of Thiersch's blue and yellow carefully 

 mixed and filtered make a good green. 



COLD TRANSPARENT INJECTIONS. 



Beale's Blue. 



Glycerin, 1 ounce. 



Alcohol, 1 " 



Ferrocyanide of potassium, .... 12 grains. 

 Tincture of perchloride of iron, . . . 1 drachm. 



Water, 4 ounces. 



