ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 509 



Mode of Investigating Echinorhynchi.* — Dr. E. Koehler finds that 

 the tissues of Echinorhynchi can be well fixed by the employment of a 

 sublimate solution acidified to saturation by acetic acid (Koulle's liquid). 

 This reagent has the advantage over osmic acid of not producing after- 

 coloration, and as animals generally die in it without contraction it is 

 additionally useful. The fixation of the internal organs is complete ten 

 minutes or a quarter of an hour after immersion. He did not find any 

 difficulty, such as w r as experienced by Saeftigen, in staining the tissues, 

 though the coloration is a little slower than usual. Any want of success 

 is due to trying staining en masse, for the cuticle is difficult to penetrate ; 

 there is no difficulty with sections. Kleinenberg's hasinatoxylin is to be 

 recommended. Anilin dyes, such as cocceinin and " rouge de Bordeaux 

 E," give very fine stains, and the latter was found good for all kinds of 

 tissues, and in very weak solutions, applied for some hours, gave good 

 colorations to pieces of Echinorhynchus heruca. With E. gigas colora- 

 tion en masse is easy if the cuticle be removed, as can easily be done. 



Preparing the Nervous System of Opheliacese.f — Dr. W. Kiiken- 

 thal places the Annelida to be examined in a mixture of chloral hydrate 

 and sea water (1 : 1000), or adds a little spirit to the sea water. The 

 animals are thus benumbed without contraction or laceration, and after- 

 wards killed in 70 per cent, spirit or sublimate. Lang's mixture hot or 

 cold, 1 per cent, chromic acid, osmic acid, picrosulphuric acid, Midler's 

 fluid, iodine alcohol, and Merkel's fluid were used for the same purpose. 



The author's method for producing nerve-preparations is as follows : — 

 (1) The fresh animals were cut up along their back, placed in a basin, 

 and covered over with 10 per cent, nitric acid, which was allowed to 

 act for ten or twelve days. They were then well washed with distilled 

 water, and then immersed for fifteen minutes in a 1 per cent, solution 

 of gold chloride, to which one drop of hydrochloric acid was added. 

 They were again washed in distilled water and placed in 5 per cent, 

 formic acid for twenty-four hours. Then frequent washing with distilled 

 water, removal of the intestinal tract and of the muscles by means of a 

 fine brush and a stream of water. Then spirit, turpentine, Canada 

 balsam. (2) The animals were slowly killed in sea water plus a little 

 Merkel's solution, spread out in a basin, and covered over with pure 

 Merkel's fluid. After twenty-four hours they were washed and trans- 

 ferred to weak spirit, stained with Grenadier's borax-carmine, then de- 

 colorised with hydrochloric acid alcohol, and after absolute alcohol and 

 turpentine, mounted in Canada balsam. (3) (According to the author 

 very suitable for material long in spirit). The animals were cut up 

 and spread out in a basin and immersed in 1 per cent, osmic acid fur 

 twelve to eighteen hours. They were then w T ashed, stained with haema- 

 toxylin, and mounted in Canada balsam. The simplest and best method 

 for cutting is as follows: — The animals hardened in 70 per cent, spirit 

 are stained with Grenacher's borax-carmine, then treated successively 

 with acidulated acohol, absolute alcohol, chloroform, and finally imbedded 

 in paraffin. The sections are stuck on with collodium-clove oil, followed 

 by turpentine oil, to which a few drops of picrie acid are added. Then 

 methyl-green, turpentine oil, pure turpentine, Canada balsam. The 

 nuclei are red, the plasma and intercellular substance green, the nervous 



* Journ. de l'Anat. et de Physiol., xxiii. (1887) pp. 614-5. 



t Jenaisoh. Zeitsehr. f. Naturwiss., xx. (1887) pp. 511-SO (3 pis.). 



