CHAPTER XXXVI. 513 



minutes, then replaces this by raw pyroligneous acid diluted with 

 8 to 10 volumes of water, and after five to ten minutes washes in 

 several changes of water, and passes through successive alcohols 

 into glycerin or balsam. 



LENSSEN (La Cellule, xiv, 1898, p. 428) for the embryology of 

 Hydatina, kills with hot saturated sublimate, dehydrates, stains 

 lightly, embeds in paraffin and stains with hsemamm. 



HIRSCHFELDER (op. tit., supra) narcotises with cocaine, and fixes 

 with Fol's picro-chromic acid. 



BEAUCHAMP (Arch. Zool. Exper., iv, 1906, p. 29) finds 1 per cent, 

 stovaine better than cocaine for some forms. He (ibid., x, 1909, 

 p. 77) fixes for five to ten minutes in 4 parts of 1 per cent, osmic acid, 

 with 1 of 6 per cent, sublimate, and 5 of 5 per cent, bichromate of 

 potash, and 1 drop of acetic acid for each 2 c.c., and embeds in 

 celloidin, and then through chloroform in paraffin (three to ten 

 minutes). 



See also TOZER (Journ. Roy. Micr. Soc., 1909, p. 24). 



964. Acanthocephali. SAEFFTIGEN (Morph. Jahrb., x, 1884, 

 p. 120) obtained the best results by killing gradually with 0-1 per 

 cent, osmic acid ; the animals placed in this contract during the 

 first hours, but stretch out again and die fully extended. Similarly 

 with -1 per cent, chromic acid ; Echinorhynci live for days in it, 

 but eventually die fully extended. 



HAMANN (Jen. Zeit., xxv, 1890, p. 113) has succeeded with sub- 

 limate, and also with alcohol containing a little platinum chloride. 



KAISER (Biblioth. Zool, H. vii, 1 Halfte, 1891, p. 3) found that a 

 saturated aqueous solution of cyanide of mercury, warmed to 

 45 to 50 C., and allowed to act for from fifteen to sixty minutes, 

 and then washed out with 70 per cent, alcohol, was the best of all 

 fixing media. 



965. Nematodes. The impermeable cuticle is a great obstacle to 

 preparation. According to Looss (Zool. Am., 1885, p. 318) this 

 difficulty may be overcome in the manner described in 545. 



Wash in 1 per cent, saline (if necessary) and fix in boiling 70 per 

 cent, alcohol ; store in fresh 70 per cent, for examination. If this 

 method is properly applied the worms will die extended and straight. 

 For examination transfer to 70 per cent, alcohol made up with 5 per 

 cent, glycerine. Place small bottle of this fluid, plus worms, on 

 incubator at 60 C., and allow to evaporate slowly for about twenty- 

 four hours or even two days, which finally leaves the worms in 

 viscid, almost pure, glycerine. Examine in pure glycerine, or glycerine 



M. 33 



