INVERTEBRATES 613 



gummed to a slide with euparal, dehydrates by adding aleohol 

 by drops, and adds euparal and a cover. See also Woodland, 

 Quart. Journ. Micr. Sci., xlix, 1905, p. 307. 



CCELENTERATA 



1217. Thread-Cells. Iwanzoff {Bull. Soc. Nat. Moscou, x, 1896, 

 p. 97), advises for the Nematocysts of Actiniae maceration by 

 Hertwigs' method, § 568, or better, fixation for two to five minutes 

 with vapour or osmium followed by a short washing with sea- 

 water or distilled water. 



For Medusae he also advises Hertwigs' method, loc. cit., or treatment 

 with a solution containing methyl green and gentian violet with a little 

 osmic acid. 



1218. Little (Journ. App. Mic, vi, 1903, p. 2116; Journ. 

 Roy. Mic. Soc, 1903, p. 237) kills Hydra in hot saturated sublimate 

 in 70 per cent, alcohol, washes with alcohol, stains for five minutes 

 in strong solution of methylen blue, dehydrates rapidly, clears 

 with cedar or bergamot oil, and mounts in balsam. Nematocysts 

 blue, the rest unstained. 



1219. Actinida. Amesthetise in menthol (§ 14), which will 

 take some twelve hours or more. For ordinary sea anemones, 

 formalin (5 to 10 per cent.) followed by formalin spirit is to be 

 preferred. For corals, such as Caryophyllia, Alcyonium or Gor- 

 gonia, anaesthetise, and then add hot corrosive sublimate or 5 per 

 cent, formalin, followed by cold saturated corrosive sublimate. 

 Ninety per cent, spirit, not allowed to get weaker than 70 per 

 cent., gives good results for anatomical work (Allen and Browne, 

 loc. cit.). 



John Baker's Methods for the Micro-anatomy of Sea Anemones 

 (conmiunicated). To anat;sthetisc a sea anemone, place it in a 

 finger-bowl three-quarters full of sea-water, add a pinch of menthol, 

 place it in a dark cupboard, and leave it for about twelve hours 

 (overnight is convenient). At the end of this period it will not 

 be completely anaesthetised, and the addition of a fixative will 

 be likely to cause some contraction. To avoid this, complete 

 the anaesthesia by adding, fairly gradually, 50 or 100 c.c. 

 of 30 per cent, magnesium chloride solution. (If the magnesium 

 chloride is used without the previous treatment with menthol, the 

 animal will generally contract.) Leave for an hour, and then 

 squirt the fixative with a pipette all round the animal, and, if 

 possible, into the throat. Then pour away the sea-water and 

 substitute the fixative. A convenient fixative is Heidenhain's 

 " Susa." Dealcoholisation may be done in cedar-wood oil. The 

 following staining method depends on the fact that after the use 

 of a fixative (such as Susa) which contains formaldehyde, carmine 

 is inhibited from staining all parts other than the mesogloea. It is 



