METHODS KOlt INVMUTEUKATUS. 473 



The solution should be employed cold in general for (lymno- 

 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-blue intra vitam method, see Chapter 

 XVI; also HAD/I, Arb. ZooL lust. Wien, xvii, 1909, <p. 225. 



909. Medusae : Fixation. For narcotisation see 17. 



Trachymedusse and Acalephaj 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 



O ' 



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



910. BIGELOW (Mem. Boston Soc. nat. Hist., v, 1900, p. 193) fixes the 

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

 per cent, solution of cupric 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 HERTWIGS (Nervensy stein 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 

 BEDOT (Arch. Sci. phys. et nat., xxi, 1889, p. 550), 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), FRIEDLANDER (Biol. Centratb., x, 1890, 

 p. 483), and DAVJDOFF (Anat. Anz. t xi, 1896, p. 505) see 

 previous editions. Lo BIANCO fixes most forms with the 

 mixture given 910. 



For preserving, according to WEBEK, formaldehyde is 

 better than alcohol. DAVIDOFF (loc. cit.) fixes in it. + 



