ZOOLOGY AND BOTANY, MIOROSOOPY, ETC. 329 



Flemming's clirom-osmium-acetic acid, and safranin staining give^ good 

 results. Fixation with 3 per cent, nitric acid produced vacuoles in the 

 yolk, and was, therefore, of but little use. 



Preparation of the Embryo of the Fresh-water Crayfish.*— Dr. H. 

 Eeichenbach hardens the eggs by placing them in water, which is gradually 

 heated up to 60° or 70° C. (rupture of the chorion does not damage the 

 embryo) ; they are then hardened in a 1 to 2 per cent, bichromate or • 5 

 per cent, chromic acid for 24 hours ; next washed for a similar period, and 

 then transferred first to 70 per cent, spirit and lastly to absolute alcohol. 

 The chorion is then opened, and the embryo separated from the yolk by 

 means of a sharp knife, and stained with picrocarmin. The yolk stains 

 yellow, the plasma and nuclei red ; then water, alcohol, cloves, and balsam. 



Preparation of Copepoda.t — Dr. J. Yosseler recommends as the 

 simplest method for killing, hardening, and staining Copepoda, to place 

 them for about 12 hours in a mixture of Flemming's solution 1 part, 

 water 2 parts, and then, after washing, to harden in spirit ; mount _ in 

 Venice turpentine. The animals also may be killed by the gradual addition 

 of alcohol to the water in which they are contained. After having been 

 placed in a mixture of equal parts of glycerin and water from 10 to 14 

 days they may be examined. Permanent preparations should be after- 

 wards placed in absolute alcohol and mounted in Venice turpentine. 



Preparation of Lumbricida.J— Dr. H. Ude, in order to demonstrate 

 the anatomy of the pores and the histology of the body-wall, employed 

 the following methods : — 



1. Living earthworms were placed in ■ 5 per cent, chromic acid and 

 hardened therein for eight to ten hours, washed in water, and trans- 

 ferred to 70 per cent, alcohol, then stained with Hamann's neutral acetic 

 carmine, 70, 80, 90, 100 per cent, spirit, chloroform, chloroform- 

 paraffin, pure paraffin. Eesults : Hypodermis good ; longitudinal muscles 

 destroyed. 



2. The worms were killed in boiling water and the bodies, stretched on 

 cork, were then treated for eight hours with 1 part concentrated picro- 

 sulphuric acid to 3 parts distilled water. After washing they ^ were 

 stained with Grenacher's borax-carmine. Eesults excellent, but if the 

 colour be withdrawn with hydrochloric acid alcohol the cuticula and hypo- 

 dermis are damaged. 



3. If the animals are to be preserved in spirit they are previously 

 narcotized with chloroform vapour, in order to prevent too great contrac- 

 tion. Stain with borax-carmine. 



Preparation of Rhabdocoelous Turbellaria.§— Dr. M. Braun prepares 

 whole specimens on a slide by running under the cover-glass a mixture of 

 3 parts Lang's fluid and 1 part of a 1 per cent, osmic acid solution. 

 Directly the animals become opaque the superfluous fluid is removed with 

 blotting-paper, and then replaced by 45 per cent, spirit and afterwards by 

 70 per cent, alcohol. The cover-glass is then removed, and 96 per cent, 

 alcohol applied. In a few minutes the latter is replaced by 1 or 2 drops of 

 alum-carmine which stains in 2 or 8 minutes. Wash in water, transfer to 

 alcohols of gradually increased strength up to absolute ; clear up in oil of 

 cloves or creosote, and mount in balsam. 



* Abh. Senckenb. Naturf. Gesell., xiv. (1886) 137 pp., 14 pis. 

 t Inaug.-Diss. Stuttgart, 1886. Cf. Zeitschr. f. Wiss. Mikr., iii. (1886) p. 400. 

 % Zeitschr. f. Wiss. Zool., xliii. (1886) pp. 87-143 (1 pi.). 



§ Arch. Naturk. Liv.-Esth. u. Kurlands, x. (1885). Cf. Zeitschr. f. Wiss. Mikr., ni. 

 (1886) pp. 398-9. 



1887. Z 



