470 CHAPTER XXXVI. 



and stained with dilute borax-cramine. It is important (for 

 preparations that are not destined to be sectioned) to use 

 only dilute borax-carmine, as the strong solution produces 

 an over-stain that cannot easily be reduced. 



Narcotisation by chloral hydrate before fixing is useful, 

 especially for the study of Pentacrinus Iarva3 and of the 

 voung Si/naptse formed from Auricularia. Without this 

 precaution you generally get preparations of larvae either 

 shut up (Pentacrinus) , or entirely deformed by contraction 

 (young Synaptae). 



See also MACBRIDE 011 the development of Amphiura squamata, 

 Quart. Jo urn. Micr. Sci., xxxiv, 1892, p. 131 (osmicacid followed by liquid 

 of Midler and alcohol ; decalcification with nitric acid in alcohol ; stain- 

 ing with Mayer's paracarmine or hsemahmi) ; and SEELIGER on the de- 

 velopment of Antedon, Zoul. Jahrb., Abth. Aunt., vi, 1892, p. 161. 



MACBRIDE (Quart. Journ. Micr. Sci., xxxviii, 1896, p. 340) fixes larvae 

 of Asterina in osmic acid, brings into liquid of Miiller for twelve to four- 

 teen hours, imbeds in celloidiii followed by paraffin (see 171). and 

 stains sections with carmalum or Delafield's hamiatoxylin, best after a 

 foregoing stain of twenty-four hours in borax carmine. 



MAYER (Gr-itndzuye, LEE and MAYEK, 1910, p. 486) arranges 

 a number of fixed iind stained Plutei on a sheet of gelatin 

 foil gummed to a slide with euparal, dehydrates by adding 

 alcohol by drops, and adds euparal and a cover. See also 

 WOODLAND, Quart. Journ. Micr. Sci., xlix, 1905, p. 307. 



Coelenterata. 



899. Thread-cells. IWANZOFF (Bull. Soc. Nut. M< scou, x, 189(>, 

 p. 97) advises for the Nematocysts of Actinia) maceration by the HERT- 

 WIG'S method, 534, or better, fixation for two to five minutes with 

 vapour of osmium followed by a short washing with sea water or distilled 

 water. 



For Medusae he also advises the HERTWIG'S method, 534, or treat- 

 ment with a solution containing methyl green and gentian violet with a 

 little osmic acid. 



900. LITTLE (Journ. App. Mic., vi, 1903, p. 2116; Journ. 

 Hoy. Mic. Soc., 1903, p. 237) kills Hydra in hot saturated 

 sublimate in 70 per cent, alcohol, washes Avith alcohol, stains 

 for five minutes in strong solution of methyleii blue, dehy- 



