356 SOME ZOOLOGICAL METHODS. 



solution, if I understand the writer justly, no secretion of 

 mucus will occur. 



707. Injection of Acephala (FLEMMING, Arch. f. mik. Anat., 

 1878, p. 252). To kill the animals, freeze them in a salt-and- 

 ice mixture, and throw them for half an hour into lukewarm 

 water. They will be found dead, and in a fit state for in- 

 jection. Chloroform and ether are useless. The injection- 

 pipe may be tied in the heart ; but when this has been accom- 

 plished there remains the problem of occluding cut vessels 

 that it is impossible to tie. To this end, after the pipe has 

 been tied, the entire animal is filled and covered up with 

 plaster of Paris. As soon as the plaster has hardened, the 

 injection may be proceeded with. 



708. Foot- glands of Gastropoda (HOUSSAY, Arch, de Zool. 

 exper., 1883, p. 171). Harden the foot for twenty-four to 

 forty-eight hours in 50 per cent, alcohol, make sections, and 

 stain them with picro-carmine. Treat them first with 30 per 

 cent, alcohol, and then stain in a 0*1 to 0'2 per cent, solution 

 of methyl-green in 60 per cent, alcohol. Dehydrate and 

 mount in balsam. The foot-glands alone are coloured green. 



709. Eyes of Gastropoda (FLEMMING, Arch.f. mik. Anat., 1870, 

 p. 441). The first difficulty here is to obtain the excision of 

 an exserted eye. It is impossible to sever the exserted 

 peduncle in a living animal without its retracting at least 

 partially before the cut is completed. Never mind that; 

 make a rapid cut at the base, and throw the organ into very 

 dilute chromic acid, or 4 per cent, bichromate ; after a short 

 time it will evaginate, and remain as completely erect as if 

 alive. Harden in 1 per cent, osmium, in alcohol, or in bichro- 

 mate. 



CARRIERE (Zool. Anz., 1886, p. 221) gives the following in- 

 structions : Remove the eye together with a portion of the 

 tentacle, and fix it by exposing it for some minutes to vapour 

 of osmium. Make sections according to the usual methods, 

 and fix them on a slide with Schallibaum's collodion. Stain 

 them with picro-carmine ; or, first depigment them by very 

 careful treatment with very dilute eau de Javelle, and then 

 -tain with picro-carmine. Mount in dammar. Successful pre- 

 parations show the tissues perfectly preserved ; but Carriere 



