14 KILLING 



thuriae and other Echinoderms in this way. Ward (see Amer. 

 Nat., XXV, 1891, p. 398) has succeeded with Hydroids, Actiniae, 

 and similar forms, and Uexkull [Mitth. Zool. Stat. Neapel, xii, 

 1896, p. 463) with Echinids. 



Marine animals are sometimes successfully killed by simply 

 putting them into spring water. 



Warm Water will sometimes serve to immobilise and even 

 kill both marine and fresh- water organisms. 



Carbonic Acid Gas has been recommended (by Fol, Zool. 

 Anz., cxxviii, 1885, p. 698). The water containing the animals 

 should be saturated with the gas. The method is stated to 

 succeed with most Coelenterata and Echinodermata, but not 

 with Molluscs or Fishes. We have had most excellent results 

 with small Annelids and Hirudinea. It is not necessary to 

 employ a generator for obtaining the gas. It suffices to take an 

 ordinary " soda-water " syphon, and squirt its contents into the 

 water containing the animals. 



Narcotisation is very rapidly obtained with very small animals, 

 but much more slowly with larger ones. For instance, Stylaria 

 proboscidea, we find, is paralysed in a few seconds ; a small Nephelis 

 of 15 or 20 mm. in length, will require about five minutes ; and a 

 large Nephelis, of from 10 to 15 cm., will require as many hotirs. 



Uexkull {Mitth. Zool. Stat. Neapel, xii, 1896, p. 463) has 

 paralysed Echinids very rapidly with carbonic acid, likewise a 

 small Teleostean fish ; whilst Scyllium and Crustaceans were 

 affected much more slowly, and mussels not at all. 



26. Peroxide of Hydrogen. Volk {Zool. Anz., xix, 1896, 

 p. 294) kills Rotatoria by means of one or two drops' of a 3 per 

 cent, solution added to 1 c.c. of the water containing them. 



27. Anaesthesia of Animals for Cell Studies. J. McA. Kater 

 {Science, vol. 82, 1935) finds sodium amytal satisfactory for 

 rabbit liver, there being no difference between control and 

 anaesthetised animals after half an hour. The dose was 3 grains 

 for an animal of 5 to 6 lbs. weight. Hirsch (Z. Zellf., 1932) and 

 DuTHiE {Proc. Roy. Soc. B., 1933) used Cibalgin for mice, 0-6 c.c. 

 of ^Q solution. 



