HYDROXYLAMIN. 13 



15. Cocain (RICHARD; Zool. Anz., 196, 1885, p. 332) has 

 been found to give good results. Richard puts a colony of 

 Bryozoa into a watch-glass with 5 c.c. of water, and adds 

 gradually 1 per cent, solution of hydrochlorate of coca'in 

 in water. After five minutes, the animals are somewhat 

 numbed, and half a cubic centimetre of the solution is 

 added, and the tentacles are caused to contract by irritating 

 them with a needle. Ten minutes later the animals should 

 be found to be dead in a state of extension. 



This method is stated to succeed with Bryozoa, Hydra, 

 and certain worms. 



It has been pointed out (by GOBI, in the paper quoted above) that unfor- 

 tunately when fixing agents, such as sublimate solution, are added to the 

 animals, the cocain is thrown down on them as a white precipitate. 



16. Hydroxylamin. HOFEE (Zeit.f. wiss. Mik., vii, 3, 1890, 

 p. 318) has employed hydroxylamin as a paralysing agent 

 with success with the most varied animal forms. Either the 

 sulphate or the hydrochlorate of the base may be used. He 

 recommends that the hydrochlorate be taken. This, as found 

 in commerce, is usually contaminated with HC1. It should 

 be dissolved in water (spring or sea-water, according to the 

 habitat of the organisms in no case distilled water) and 

 the solution exactly neutralised by addition of carbonate of 

 soda. A 1 per cent, solution should be made up, and further 

 diluted for use. The organisms are placed in the diluted 

 solution, which may be taken of a strength varying from 

 0*1 per cent, used for thirty minutes or less (as for Infusoria) 

 to 0*25 per cent., used for from fifteen minutes to one hour 

 (Hydra), 1 per cent., one half to two hours (Hirudo), or as 

 much as ten to twenty hours (Helix and Anodonta). 



It should be remembered that hydroxylamin is an extremely 

 powerful reducing agent. Care must therefore be taken not 

 to treat the paralysed animals with easily reducible fixing 

 agents, such as osmic acid, chromic acid, sublimate, chlorides 

 of gold or platinum, &c., unless it have been possible first to 

 sufficiently wash out the hydroxylamin with water. 



17. Chloride of Magnesium TULLBEBG (Arch. Zool. Exper. et Gen., 

 x, 1892, p. 11 ; Journ. Roy. Mic. Soc., 1892, p. 435) has obtained some 

 results with this salt. For Actiniae, a 33 per cent, solution of the salt is to 

 be very slowly added to the water containing the expanded animal, until the 

 vessel contains one per cent, of the salt (thus for one litre of sea-water 



