636 SUMMARY OF CURRENT RESEARCHES RELATING TO 



but without touching the legs. This brushing with oil of cloves must 

 be repeated from time to time as it sinks into the body. When a 

 creature is ready, which can only be learned by experience, a large 

 drop of oil of cloves, not benzole, may be put on; when this has 

 thoroughly dissolved the balsam, but not before, the specimen may be 

 moved and mounted, or further soaked in oil of cloves. 



Preparing the Liver of the Crustacea.* — For the study of fresh 

 tissues J. Frenzel places a small piece of the organ on the slide, in 

 the hlood of the individual from lohich it was taken ; or, in sea-water 

 diluted until the salt contained amounts to about 1^-2 per cent, (one 

 part distilled water and one part sea-water from the Bay of Naples). 

 The so-called " physiological salt-solution " (3/4 per cent.) worked 

 unfavourably, causing maceration. 



Various fluids were employed for killing and hardening, partly 

 for determining the effect of different reagents on the nuclei and 

 the protoplasm, and partly for finding the best means of preparing 

 the object for sectioning. 



Very good preparations were obtained with warm alcohol from 

 70-90 per cent. ; while direct immersion in absolute alcohol did not 

 prove advantageous. This treatment gave good results for the cell- 

 protoplasm, but destroyed the structure of the nuclei. Still better 

 results were obtained for the cells (not for the nuclei) by adding a 

 few drops of iodine to 70 per cent, alcohol. 



The most satisfactory results were reached by immersing the 

 object in a saturated aqueous solution of corrosive sublimate from 

 ten to thirty minutes, then washing with water, and finally replacing 

 the water gradually with alcohol. 



Perenyi's fluid gave best results when combined with corrosive 

 sublimate. The object was left from five to ten minutes in the 

 first-named fluid, then transferred to the second and left for the same 

 time. 



While these methods were good for the Decapods, Amphipods, and 

 PhronimidEe, the Isopods required a different treatment. With these, 

 Kleinenberg's picro-sulphuric acid, diluted with an equal volume of 

 water, and allowed to act 15-20 minutes, gave much better preparations 

 than the sublimate solution. 



Preparing" Alcyonaria.f — In studying the mesenterial filaments 

 of the Alcyonaria, E. B. Wilson obtained the best results in the 

 following manner. 



The animals were suddenly killed by momentary immersion in a 

 mixture of 1 part strong acetic acid and 2 parts of a concentrated 

 solution of corrosive sublimate in fresh water. After being quickly 

 washed, they were transferred to a concentrated solution of sublimate 

 in fresh water and left two or three hours ; the internal cavities 

 being injected with the solution, where this was possible. They 

 were then thoroughly washed in running sea-water, then in distilled 



* MT. Zool. Stat. Neapel, v. (1884) p. 51. Amer. Natural., xviii. (1884) 

 pp. 556-7. 



t MT. Zool. Stat. Neapel, v. (1884) p. 3. 



