METHODS J.''OR INVGRTEBEATJiS. 473 



The solution should be employed cold ia general for Grymno- 

 blastea, hot for most Calyptoblastea. 



Ether attentively administered gives good results with 

 Campanularidae. Hydra is very easily killed by a drop of 

 osmic acid on a slide. 



For the methylen-hlue intra vitam method, see Chapter 

 XVI ; also Hadzi, Arh. Zool. Inst. Wien, xvii, 1909, p. 225. 



909. Medusae : Fixation. — For narcotisation see § 17. 



Trachymedusse and Acalephte may be fixed in the usual 

 way in chromic or osmic mixtures. Osmic acid may be added 

 to the sea water containing the animals, which should be 

 removed to spring water as soon as they begin to turn brown. 



910. BiGBLOW {Mem. Boston 8oe. iiat. Hist., v, 1900, p. 193) fixes the 

 scyphistomes of Cassiopeia in Lo Bianco's mixture of 10 parts of 10 

 per cent, solution of ouprio sulphate with 1 of saturated sublimate, and 

 hardens them in 5 per cent, bichromate of potash. 



911. Medusae : Sections. — Paraffin and collodion are certainly 

 not satisfactory as all-round methods for these watery 

 organisms. The Heetwigs {Nervensystem der Medusen, 1878, 

 p. 5) imbedded in liver with the aid of glycerin gum, and 

 hardened the objects and the mass in alcohol. 



See also Joliet's glycerin-gum method, and the gelatin 

 methods in Chapter VIII. 



912. Medusae : Maceration. — See, especially for the study 

 of the nervous system, § 534. Doubtless in many cases the 

 pyrogallic acid reaction, § 374, would give enhanced differen- 

 tiation. 



913. Siphonophora. — For the cupric sulphate method of 

 Bbdot {Arch. Sci. phys. et nat., xxi, 1889, p. 556), which is 

 admirable for the preparation of museum specimens, but not 

 necessary for histological work, as well as for those of Lo 

 Bianco [op. cit., p. 454), Feiedi.andek {Biol. Centralb., x, 1890, 

 p. 483), and DAVJDOtT {Anat. Anz., xi, 1896, p. 505) see 

 previous editions. Lo Bjanco fixes most forms with the 

 mixture given § 910. 



For preserving, according to Webee, formaldehyde is 

 better than alcohol. Davidoee {loc. cit.) fixes in it. 



