ZOOLOGY AND BOTANY, MICBOSCOPYj ETC. 1045 



may be best killed by being plunged in a quantity of E. van Beneden's 

 fluid, wbicli consists of a saturated solution of corrosive sublimate in 

 distilled water 3 parts, and crystallizable acetic acid 1 part. Specimens 

 should be left in tbis fluid for from five to twenty-five minutes according 

 to tbeir size, and then washed in pure water. They should then be 

 placed in alcohol of 45°, then 60°, 70°, and finally 80°. For histological 

 purposes 90° and absolute alcohol should also be used. K necessary the 

 quantity of acetic acid may be diminished. 



For animals which contract rapidly it is best to use ordinary alum. 

 Specimens are put in glass dishes with sufficient water to enable them to 

 expand ; when expanded some crystals of alum are quietly put near 

 them ; as these dissolve slowly the animals are killed gradually. Several 

 hours are necessary for this reagent. They are then washed clean of 

 alum, fixed with dilute solutions of Van Beneden's fluid ; then washed 

 with water and treated with a series of various strengths of alcohol. 



Preparation of Embryos of Asterias.* — Mr. J. W. Fewkes, in his 

 investigations into the development of Asterias, killed the young forms 

 in 35 per cent, alcohol ; they were then rapidly passed through various 

 grades (50, 70, 90 per cent.) to absolute alcohol. They were then 

 clarified in clove-oil, and mounted in balsam. Those which were 

 stained were carried from 70 per cent, alcohol into Grenacher's alcoholic 

 borax-carmine, washed, afterwards placed in from 90 per cent, to 

 100 per cent, alcohol, then removed to clove-oil or balsam. The pre- 

 parations mounted without staining show very well the relation of the 

 plates to each other, but it is necessary to use a staining fluid to brino- out 

 the tissues of the organs in the immediate vicinity of the calcareous 

 skeleton. Mr. Fewkes, who used chloroform for clarifying purposes in 

 bis study of AmpMura, finds that clove-oil is to be preferred. 



Investigation of Generative Products of Spongilla.t — Herr K. 

 Fiedler has fixed and preserved the pieces of Spongilla, which he ex- 

 amined, with absolute alcohol and a mixture of alcohol and sublimate • 

 the latter consisted of one part of cold saturated sublimate solution, one' 

 part of 70 per cent, alcohol, and one part of distilled water. Kleinen- 

 berg's picric sulphuric acid and Flemming's chrom -osmium-acetic acid 

 mixture were also used with satisfactory results. Pieces were stained 

 with Grenacher's borax-carmine and Schweigger-Seidel's hydrochloric 

 acid and carmine. Smaller pieces were well stained with Bohmer's 

 haematoxylin and with picrocarmine. Imbedding was generally effected 

 in paraffin, rarely in celloidin. The thickness of the sections varied 

 between 1/50 and 1/160 mm. Lyons blue was found to be especially 

 useful in staining sections, for on being washed with ammoniacal alcohol 

 the blue coloration was limited to the yolk-granules of the egg, and this 

 showed up the red-stained nuclear structures. Sections of tissues pre- 

 served in picro-sulphuric acid showed, when stained with hematoxylin, 

 a double coloration, the nuclei being of a bluish-violet and the vitelline 

 constituents of a yellowish or feebly red tone. 



New Method for Marking Root-hairs and for Hardening and 

 Staining Plant-cells, f— In his work on ' The Eolations between Func- 



* Bull. Mus. Comp. Zool. Camb. U.S.A., svii. (1888) pp 3-4 

 t Zeitschr. f. Wiss. Zool., xlvii. (1888) pp. 86-8. 



X ' Ueber die Beziehungen zwischen Function und Lage des ZeUkems bei dpn 

 Pflanzen,' 8vo, Jena, 1887, 135 pp. (2 pis.). 



