ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 535 



5. Remove the vitelline membraue by the aid of dissecting forceps, 

 and the yolk by gently shaking the watch-glass and by occasional use 

 of a needle. The yolk can sometimes best be washed oflf by means of 

 a pipette. 



6. Wash in water (several times changed). 



7. Colour deeply with carmine or hematoxylin. 



8. Remove excess of colour by soaking a few minutes in a mixture 

 of water and glycerin in equal parts, to which a few drops (about 

 1 per cent.) of hydrochloric acid have been added. 



9. Wash and treat thirty minutes with mixture of alcohol (70 per 

 cent.), 2 parts ; water, 1 part ; glycerin, 1 part. 



10. Transfer to pure 70 per cent, alcohol, then to absolute alcohol. 

 Clarify with creosote or clove-oil, and mount in balsam. 



The above method of treatment will also serve for blastoderms 

 which are to be sectioned. 



Preparing Siphonophora.* — Dr. A. Korotneff has obtained good 

 sections of the very contractile stem of Siphonophora in the 

 following u ay : — 



After the Siphonophora has settled down a watch-glass full of 

 chloroform is floated on the surface of the fluid, and the vessel 

 covered up with a bell-jar. The animal, benumbed by the chloroform 

 vapour, becomes extended. The bell-jar is then removed, and the 

 animal suddenly immersed in some hardening fluid. The author 

 employed a 1/2 per cent, chromic acid solution and a 1 per cent, hot 

 sublimate solution. In the latter case, the animal was quickly trans- 

 ferred to 20-30 per cent, alcohol. With regard to the tentacles, it 

 may be mentioned that the mucous layer separates into long uni- 

 cellular tubes after teasing out and being treated with osmic acid. 

 These tubes, the author thinks, are glandular, as they stain deeply 

 with hfematoxylin and alum carmine. 



Preparing Spinal Ganglia.f — Herr M. v. Lenhossek found a 

 1-1 • 5 per cent, solution of superosmic acid to give most satisfactory 

 results in the study of the structure of the spinal ganglia of the frog. 

 The ganglia were left three-quarters of an hour in the fluid. Bichro- 

 mate of potassium and alcohol were used for hardening, and celloidin 

 was found most convenient for imbedding. Good results, especially in 

 the investigation of the finer relations, were obtained by the use of 

 gold chloride. 



Modification of Pancreatic Cells during active secretion. J — In 

 studying the behaviour of the cells of the pancreas during very active 

 secretion, Dr. S. W. Lewaschew used for hardening purposes alcohol 

 and concentrated solution of sublimate, which proved very satis- 

 factory. The tissue was then laid in turpentine or bergamot oil. 

 Ehrlich's haematoxylin solution gave the best staining reactions. 

 Ogata's suggestion of combined staining with various fluids — hsema- 

 toxylin, eosin, &c., was also adopted. 



* MT. Zool. Stat. Neapel, v. (1884) pp. 229-88 (6 pis.), 

 t Arch. f. Mikr. Anat., xxvi. (1886) pp. 370-453 (2 pis.). 

 X Ibid., pp. 453-85 (1 pL). 



