ZOOLOGY AND BOTANY, MICK08C0PY, ETC. 1047 



spirit-lamp. ^\'lien the jelly is melted a warm cover-glass is imposed. If 

 the mass should swell up over the cover-glass, it is easily removed when 

 cold. 



Investigation of Histology of Eunice.* — Prof. E. Jourdan reports that 

 the use of alcohol at 90 per cent, has always given him the worst results 

 with Annelids, and that the same has been the case with picric acid ; when 

 either of these reagents has been used the elements of the tissues are quite 

 beyond recognition. The use of 2 per cent, solution of bichromate of 

 ammonia, of bichloride of mercury, either saturated, as Lang's solution, or in 

 a 5 per cent, solution, was more successful. Osmic acid (1 in 200 parts) 

 was the best reagent for the study of the antennae and the delicate organs 

 in general, and was always regarded as a good means of control for 

 observations made after the use of other reagents. After the use of these 

 fixing solutions, the specimens were washed and then placed in alcohol of 

 increasing degrees of strength up to 90 per cent. The alum-carmine 

 solution of Grenacher was most used in staining. Celloidin was used at 

 the commencement of the research, but was not found to present any 

 advantage over paraffin ; the mixture of Schallibaum was found excellent 

 in fixing the pieces after placing in paraffin, and they were thus completely 

 coloured. The plates carrying the series of sections were treated with 

 various strengths of alcohol, dehydrated by absolute alcohol, and mounted 

 in Canada balsam. 



Prof. Jourdan found greater difficulty in his teasings ; the most successful 

 method was one which has been used to isolate the nerve-tubes of Verte- 

 brates. Fresh pieces were treated with one-hundredth solution of osmic 

 acid, and were then allowed to macerate in weak alcohol or even distilled 

 water. Specimens preserved for a year in bichromate of ammonia were 

 also successfully teased in a drop of h^matoxylic glycerin, to which a drop 

 of glycerin was added for examination and preservation. 



Preparing Epithelia of Actiniae.! — Dr. J. H. List used the ten- 

 tacles of Antliea cereus and Sagartia parasitica in his examination of the 

 epithelia of Actiniae. The tentacles were snipped oflf in the vessels in 

 which the animals were kept alive, and when the contraction due to the 

 irritation had passed ofi", the greater part of the sea-water was removed 

 with a pipette, only so much being left as would serve to keep the specimen 

 moist. The tissue of the tentacles was then fixed with chrom-osmium 

 acetic acid. This was allowed to act for ten minutes ; the specimen was 

 then washed, and after-hardened in spirit. 



Isolation of the elements was ett'ected by placing the tentacles in a 

 vessel containing 100 ccm. sea-water and 30 ccm. Flemming's fluid (chrom- 

 osmium acetic acid mixture). After allowing this to act for ten minutes, 

 the tentacles were transferred to a large quantity of • 2 per cent, acetic 

 acid, wherein they remained for two to three hours. The specimens thus 

 treated were afterwards placed in glycerin and water (equal volumes), and 

 there teased out. Excellent isolation-preparations of the cells of the ecto- 

 derm were thus obtained ; these kept extremely well, and further differen- 

 tiation was obtained by staining with picrocarmine. 



Breaking up Diatomaceotis Rocks4 — M. Guinard breaks up diatoma- 

 ceous rocks by putting small fragments in a test-tube and covering them 

 for about 2 cm. with crystals of commercial acetate of soda and then adding 

 one or two drops of water. (On a larger scale the proportion of water is 



* Ann. Sci. Nat.— Zool., ii. (1887) pp. 239-42. 

 t Zeitschr. f. Wiss. Mikr., iv. (1887) pp. 210-1. 

 X Bull. Soc. Belg. Micr.. xiii. (1887) pp. lSO-2. 



