ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 699 



30°, 30 c.cm. ; soda sulphate, 8 grms. ; soda chloride, 1 grm. ; methyl- 

 violet 5 B, 0*025 grm. The violet was dissolved in the glycerin, 

 diluted with half the distilled water, the salts in the other half ; the 

 two mixed and filtered when cool. The staining fluid was mixed with 

 the blood and then placed in a cell or moist chamber. The staining 

 action is well marked in 5 to 10 minutes, and attains its maximum 

 in 20 to 30 minutes. The white blood-corpuscles appear as small 

 granular violet balls, which are easily distinguished from the greenish 

 coloured red corpuscles. 



Obtaining Haemoglobin Crystals.* — Dr. St. v. Stein places a thin 

 layer of fresh defibrinated blood upon a slide, and when it begins to 

 dry at the edges, covers it over with Canada balsam, which should not 

 be too fluid as the crystals are then less permanent. As long as the 

 balsamic odour is perceptible, the specimens remain without a cover- 

 glass. The balsam layer is then removed by means of a knife 

 moistened with ether, turpentine, or oil of cloves. A cover-glass is 

 put on and sealed up with balsam or asphalte. Such preparations 

 have kept well for ten years. 



Preparing Muscle to show Nerve Extension.! — The procedure 

 used by Dr. R. Mays for making preparations to show nerve extension 

 in muscle is a combination of the osmic acid method with gold 

 staining. The addition of the gold salt is to prevent the browning 

 and clouding of the muscle substance, which occurs after osmic acid 

 only, associated with the previous swelling of the muscle in dilute 

 hydrochloric acid. Dr. Mays' procedure with thin muscle from 

 which he obtained suitable preparations is as follows : — 



The fresh muscle is placed in a mixture of • 5 per cent, gold 

 chloride solution (1 part), 2 per cent, hyperosmic acid (1 part), and 

 water 50 parts. It is then cleared up in a mixture of glycerin 

 40 parts, water 20 parts, and 25 per cent, hydrochloric acid, 1 part. 

 This procedure does not, however, prevent clouding and browning in 

 thick muscles. To avoid these inconveniences altogether, Dr. Mays 

 recommends the following method. The fresh muscle is laid for 

 12 hours in a 2 per cent, solution of acetic acid, then for 2 to 3 hours 

 in the gold-osmium solution (0 ■ 5 per cent, gold chloride solution 1, 

 2 per cent, osmic acid 1, 2 per cent, acetic acid 50). For clearing 

 up the above, glycerin mixture is used. 



Although the foregoing methods give excellent results, they fail to 

 distinguish between the intra- and hypolemmal parts of muscle ; but 

 in an appendix Dr. Mays adds a method by which this differentiation 

 becomes possible and which shows that by the gold-osmic-acid treat- 

 ment the nerve-fibres are stained to their ends, i. e. up to their 

 entrance into the muscle. The muscle is thoroughly soaked in a 

 • 5 per cent, solution of arsenious acid, and then for 20 minutes in 

 a freshly made mixture of 1 per cent, gold chloride, 4 parts ; 2 per 



* Centralbl. Med. Wiss., 1884, p. 404. 



t Zeitschr. f. Biol., xx. p. 449. Cf. Zeitschr. f. Wiss. Mikr., ii. (1885) 

 pp. 401-2. 



