18 PROFESSOR RUTHERFORD. 



2oz. ; rectified spirit, ^oz. Place carmine in a test tube, add 

 the ammonia, boil for a few seconds, let stand for an hour, 

 add the water, filter, and add the spirit and the glycerine. 

 Allow to stand exposed to the air until the odour of ammo- 

 nia is scarcely perceptible. The tissue may be steeped in this 

 fluid, or it may be injected into the blood-vessels, and allowed 

 to find its way through the capillary walls into the tissues. 

 (Beale.) Remove superfluous pigment by macerating the 

 tissue in glycerine 2 parts, water 1 part. Fix the pigment 

 by placing tlie tissue in acid glycerine (5 drops glacial acetic 

 acid, or J3 drops hydrochloric acid, to 1 oz. of glycerine). 2. 

 Magenta, most useful for staining tissues immediately. Like 

 carmine, it generally stains nuclei, nerve axial cylinders, &c. 

 Unlike carmine, it fades, and therefore it is not suitable for 

 permanent preparations. Two fluids necessary — a, 1 grain 

 crystallized magenta, 100 minims absolute alcohol, 5 oz. dis- 

 tilled water. This is used for the tissues generally. The 

 following is used for blood-corpuscles only : — b, Crystallized 

 magenta, 1 part ; rectified spirit, 50 parts ; distilled water, 

 150 parts ; glycerine, 200 parts. 3. Nitrate of silver, used for 

 blackening epithelial cement in capillaries and lymphatics 

 more especially, ^ per cent, solution of nitrate of silver in dis- 

 tilled water. Put the fresh tissue in this for one to three 

 minutes, then in very dilute acetic acid (1 to 2 per cent.) 

 for a minute or two, then place in glycerine and expose to the 

 light. Mount in glycerine or glycerine jelly. 4. Chloride of 

 gold, useful for staining nerve-fibrils. The colour produced 

 is violet. Half per cent, solution of gold chloride in distilled 

 water. Place fresh tissue in this for fifteen to twenty 

 minutes, until it is of a yellow colour, then in dilute acetic 

 acid (1 to 2 per cent.) for a few minutes. Then place in 

 distilled water and expose to the light until a tinge which is 

 sufficiently violet appears. Mount in glycerine jelly, &c. 5. 

 Osmic acid, chiefly used for the retina. It blackens certain 

 parts. (For the solution, see " How to harden Tissues.") 

 Mount in saturated solution of potassium acetate. 



Hoio to Inject. — A. Blood-vessels. 1. Injection, fluid at 

 ordinary temperatures, a, Beale's Prussian blue injection 

 with glycerine (Beale 'How to Work '), excellent when a 

 perfect injection is not desired. Preserve in acid glycerine 

 (2 drops HCl to 1 oz. glycerine). h, Watery solution of 

 soluble Prussian blue (see ' Jl. of Anatomy and Physiology,' 

 vol. i, 1st series, p. 869), also good for injecting vessels 

 when a perfect injection is not wanted. After injection with 

 h precipitate the pigment inside the vessels by immersion in 

 spirit (90 per cent.). 2. Injections solid at ordinary tempe- 



