512 METHODS FOE INVERTEBRATES. 



Lo BIANCO says killing with 0-5 per cent, chromic acid or with 

 04 per cent, chloral hydrate in sea water may be tried. Phascolo- 

 soma and Phoronis should be treated by the alcohol method, larvae 

 of Sipunculus with cocaine, 21. 



APEL (Zeit. wiss. Zool., xlii, 1885, p. 461) puts Priapulus and 

 Halicryptus into a vessel with sea water and heats on a water bath 

 to 40 C. ; or they may be thrown into boiling water, which paralyses 

 them so that they can be quickly cut open and thrown into J per cent, 

 chromic acid or picro-sulphuric acid. 



963. Rotatoria. For quieting them for study in the living state, 

 WEBER (Arch, de Biol., viii, 4, 1888, p. 713) finds that 2 per cent, 

 solution of hydrochlorate of cocaine gives the best results. Warm 

 water gave him good results for large species, such as those of 

 Hydatina and Brachionus. 



HARDY (Journ. Roy. Mic. Soc., 1889, p. 475) recommends thick 

 syrup added drop by drop to the water. HUDSON (ibid., p. 476) 

 mentions weak solution of salicylic acid. 



VOLK (Jahrb. Hamburg, wiss. Anst., xviii, 1901, p. 164) quiets 

 them in quince mucilage, 40 grm. of the seeds to 1 litre of water. 

 Qf. 1018. 



HIRSCHFELDER (Zeit. wiss. Zool., xcvi, 1910, p. 211) studies them 

 living in neutral red of 1 : 50,000. 



See also 23, 24 and 27. Methylene blue, 339, may be found 

 useful. 



Permanent preparations may be made by the method of ROUSSELET 

 (Journ. Quekett Mic. Club, v, March, 1895, p. 1) : The animals are 

 got together in a watch glass and are narcotised by adding to the 

 water at intervals a few drops of the following mixture : 



Hydrochlorate of cocaine 2 per cent, solu- 

 tion ....... 3 parts. 



Methylated spirit . . . . .1 



Water ....... 6 



As soon as the cilia have ceased to beat, or are seen to be on the 

 point of ceasing to beat, they are fixed by adding a drop of liquid of 

 Flemming or of \ per cent, osmic acid. After half a minute or less 

 the animals are taken out with a pipette, and thoroughly washed by 

 passing them through two or three watch glasses of distilled water. 

 They are then definitely mounted in a mixture of formol 2J parts, 

 distilled water 37J parts. 



ZOGRAF (Comptes Rend., cxxiv, 1897, p. 245) narcotises as ROUSSE- 

 LET, but without the spirit, fixes with osmic acid for two to four: 



55 

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