O/O SUMMARY OF CURRENT RESEARCHES RELATING TO 



annelid may be placed on a slide, teased apart under the dissecting 

 Microscope with fine needles, and then examined in a drop of the 

 macerating fluid ; or it may bo freed from its cuticula, and subjected 

 to gradual pressure under a cover-glass. This treatment causes the 

 preparation to flatten out, but does not dissociate the tissues so far as 

 to obscure the relations existing between the different layers and 

 their constituent elements. 



In some cases good results may be reached by giving light taps 

 on the cover-glass with the point of a needle for ten minutes or more. 

 In either case the progress of dissociation can be followed with the 

 Microscope. 



Specimens to be sectioned with the microtome should be so killed 

 that they remain straight and extended. They may be killed by 

 adding very slowly alcohol to the water. As soon as they cease to 

 move they should be taken out and extended on a slide, and then 

 hardened with alcohol, osmic acid, picro-sulphuric acid, chromic acid, 

 or corrosive sublimate. 



Another method of killing is to pour hot corrosive sublimate over 

 the worm after it has been stretched out on a dry slide. A mixture 

 of osmic acid (1 per cent.) and chromic acid (1/5 per cent.) in equal 

 parts was also employed with some success. 



For colouring, borax carmine was used after sublimate and 

 chromic acid ; picrocarminate of ammonia after alcohol, osmic and 

 picric acids ; hematoxylin and anilin dyes after chromic acid. 



Preparing the Nervous System of Myzostoma.* — Dr. F. v. 

 Wagner preserves the material for examination partly in picrosul- 

 phuric acid and partly in Lang's fluid. A hot saturated solution of 

 sublimate was found to be the best fixative. Picrocarmine was prin- 

 cipally employed as a staining agent. To obtain distinct staining 

 of the nuclei of the abdominal ganglia the animals were 

 left in picrocarmine five to seven days ; in alum carmine ten to 

 twelve days. When picrocarmine is used the superfluous staining 

 matter and acid should be removed by long immersion in weak spirit. 

 The sections, which were from • 01 to • 015 mm. thick, were fixed by 

 Giesbrecht's method. In order to bring the outline of the nervous 

 system and the nerve-trunks into view, moderate crushing under the 

 cover-glass is employed. 



Natural Preservation of Rotifera and Pond Organisms.! — Mr. 

 E. B. L. Bray ley, by the following formula (which he thinks is 

 original), has been enabled to mount, amongst others, Melicerta, 

 (Ecistes, Stepharioceros, Asplanchna, Synchseta, Eosphora, Scandium, 

 &c, the tube-dwellers all fully extended from their tubes, and the 

 others with cilia exserted in a natural manner. In the transparent 

 forms the internal structure can be easily studied. 



Chromic acid, 2 gr. ; saturated aqueous solution of salicylic acid, 

 1/4 oz. ; distilled water, 1 oz. Add about two drops of the above to each 



* F. S. Leuckart, 52 pp., Graz, 1886 (1 pi.). Cf. Zeitschr. f. Wiss. Mikr., iii. 

 (1886) p. 84. 



t Sci.-Gossip, 1886, pp. 149-50. 



