474 CHAPTER XXXTV. 



acid. The fixing agent is allowed to act for half a minute 

 or less, after which 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 2^ per cent, solution of formaldehyde 

 (formol 2 parts, distilled water 37^ parts). See also 455. 



For some details concerning variations of this method 

 adapted to the preservation of the different forms, see the 

 paper quoted. 



ZOGRAF (Gomptes Read., cxxiv, 1897, p. 245; Zeit.f. ivisv.. 

 Mil-., xiv, 1897, p. 380 ; Journ. Roy. Mic. Soc., 1897, p. 173)' 

 narcotises as ROUSSELET, but without the spirit, fixes with 

 osmic acid for two to four minutes, then replaces this by raw 

 pyroligneous acid diluted with eight to ten. volumes of water, 

 and after five to ten minutes washes in several changes of 

 water, and passes through successive alcohols into glycerin 

 or balsam. 



See also 25 (VoLK). 



CONSER (Trans. Amer. Mic. Soc., xvii, 1896, p. 310) narcotises with 

 cocaine, and fixes with 20 per cent, forrnol followed by O'o per cent, chromic- 

 acid. 



854. Acanthocephali. It is very difficult to kill Echino- 

 rhynci so as to have the animals duly extended and the 

 tissues well preserved. Neither corrosive sublimate nor 

 strong osmic acid will, as a rule, attain this end, even after 

 preliminary intoxication with tobacco smoke or chloroform, 

 the animal thus treated dying contracted. 



HAMANN, however (Jen. Zeit. /. Naturw., xxv, 1890, p. 

 113; Zeit.f. iviss. Mik., viii, 2, 1891, p. 209), has succeeded 

 with sublimate, and also with alcohol containing a little 

 platinum chloride. 



SAEMTIGEN (Morphol. Jahrb., x, 1884, 120; Journ. Roy. 

 Mic. Soc. [N. S.], v, 1885, p. 147) obtained the best results 

 by killing gradually with O'l per cent, osmic acid; the 

 animals placed in this contract during the first hours, but 

 stretch out again and die fully extended. 



Another method of killing is treatment with O'l per cent, 

 chromic acid ; Echinorhynci live for days in it, but eventu- 

 ally die fully extended. 



KAISER (BiUiofh. Zool., H. vii, 1 Halfte. 1891; Zeit. J\ 



