446 SOME ZOOLOGICAL METHODS. 



simple process, suggested to me by Prof. DU PLESSIS, of fixing 

 with hot (almost boiling) water. On the few occasions on 

 which I have tried it the animals have died in extension, 

 without vomiting their proboscis ; and I think it is certainly- 

 worth trial, especially for the larger forms. 



I have tried FOETTINGEE'S chloral hydrate method ( 14). 

 My specimens died fairly extended, but vomited their pro- 

 boscides. According to S. Lo BIANCO narcotisation with a 

 solution of 0*1 to 0*2 per cent, in sea water is found successful 

 at Naples. For the smaller forms Brocher's monobromated 

 camphor, 811, may be found useful. 



DE CASTELLAENAU (Estacion Zool. de NapoleSj p. 137) says 

 that Nemerteans can be successfully narcotised by Eisig's 

 alcohol method, described 13, and I think the process may 

 be a good one for some of the larger forms. 



DENDY (see Journ. Roy. Hie. Soc., 1893, p. 116) has suc- 

 ceeded with Geonemertes by exposing it for half a minute to 

 the vapour of chloroform. 



Intra vitam staining with methylen blue will be found 

 useful in some cases. For the application of the methylen- 

 blue method to the study of the nervous system see BURGEE, 

 in Mitth. Zool 8 tat. Neapel, x, 1891, p. 206. 



For staining fixed specimens in toto I hold that it is well- 

 nigh necessary to employ alcoholic stains, for even the most 

 delicate species are not satisfactorily penetrated by watery 

 stains in any reasonable lapse of time. Borax-carmine or 

 Mayer's alcoholic-carmine may be recommended; not so 

 cochineal or haematoxylin stains, on account of the energy 

 with which they are held by the mucin which in general 

 exists in such great abundance in the skin of these animals. 



Sections by the paraffin method, after penetration with oil 

 of cedar (chloroform will fail to penetrate sometimes after the 

 lapse of weeks). 



836. Nematodes. The extremely impermeable cuticle of 

 these animals is a great obstacle to preparation. According 

 to Looss (Zool. Anz., 1885, p. 318) this difficulty may be 

 overcome by treating the animals (or their ova, which are in 

 the same case) with eau de Javelle or eau de Labarraque, in 

 the manner described in 557. 



For fixing, most recent authors recommend sublimate 



