530 SUMMARY OF CURRENT RESEARCHES RELATING TO 



scribes a method for demonstrating the primitive neuro-fibrils in the 

 ganglion-cells and the nerve-fibres of Vertebrata and Invertebrata ; at 

 the same time the Golgi-network is also stained. The fresh material, 

 in pieces 4-10 mm. thick, is placed in 3-7*5 per cent, nitric acid for 

 24 hours, and then transferred to 96 per cent, alcohol for 12-24 hours 

 or more. The blocks are next immersed for 12-24 hours in the follow- 

 ing solution: — Ammonia (sp.gr. •95-0*96) 1 part, water 3 parts, 

 alcohol (96 per cent.) 8 parts. The temperature should not exceed 

 20° C. After this the blocks are again removed to alcohol for 6—12 

 hours, and then treated with acid-alcohol: — hydrochloric acid (sp. gr. 1 • 18 

 = 37 per cent.) 1 part, water 3 parts, alcohol (96 per cent.) 8-12 parts. 

 When this step is finished (the time required is not stated) the pieces 

 are again transferred to alcohol for 10-24 hours before they are im- 

 mersed in water (2-6 hours). The acid-alcohol stage should be omitted 

 when the cells have many fibrils, and for obtaining good pictures of the 

 Golgi-reticulum in the anterior cornua of the spinal cord. The blocks 

 are now placed in 4 p>er cent, solution of ammonium molybdate for 24 

 hours. After having been washed in distilled water, the blocks are re- 

 moved to 96 per cent, alcohol (10-24 hours), and then to absolute 

 alcohol (10-24 hours). After this xylose or toluol and paraffin. The 

 sections, 10 jjl thick, are stuck on the slide with Mayer's albumen- 

 glycerin. 



The slide is now carefully washed with water to remove all traces of 

 alcohol from the section, and its under surface and edges wiped dry. 

 The preparation is covered with a layer of distilled water, 1^-2 mm. 

 thick, and the slide placed in an incubator at 55°-60° for 2-10 minutes. 

 The water is then poured off, and replaced by a similar layer of toluidin 

 blue solution (1-3000). The slide is then incubated for 10 minutes, 

 after which the superfluous stain is removed, and the slide immersed in 

 96 per cent, alcohol for 3/4—2 minutes, during which time the unmor- 

 danted pigment is removed. When no more colour comes away, the 

 preparation is transferred to absolute alcohol, then to xylol, and mounted 

 in balsam. The procedure appears to require considerable care, and a 

 large number of cautions and much advice to prevent failure at the 

 various stages are given. 



The procedure for Invertebrata is slightly different. The animals 

 may be fixed with sublimate (12 hours), treated with iodine-alcohol 

 (24 hours), and then imbedded. The sections (Hirudo) are placed for 

 10 minutes in 1 per cent, solution of ammonium molybdate (25°— 30° C), 

 washed with distilled water for 10 minutes, and then stained with 

 1-3000 toluidin-blue for 5 minutes at 58° C. For demonstrating the 

 fibrils in the cells, the ammonia aud hydrochloric acid stages must be 

 passed through. The sections are differentiated in aqueous solution of 

 ammonia or in alcoholic solution of sodium carbonate. 



Microtomists' Vade Mecum.* — Mr. A. B. Lee's Microtomists' Vade 

 Mecum or Handbook of the Methods of Microscopic Anatomy, has 

 reached its fifth edition. It is only three years since the fourth edition 

 appeared, and, excellent as it was, its successor is better. The text has 

 undergone thorough revision, some portions, notably the chapter on 



* London (J. and H. Churchill), 1900, xiv. and 5o2 pp. 



