ON THE METHODS OF MICROSCOPICAL RESEARCH 

 IN USE IN THE NAPLES AQUARIUM. 

 SUMMARY (By GEO. BEOOK, F.L.S.) of a Papee by Dr. Paul Maier in the 



'^MlTTHEILUNGEN- A. D. ZOOLOG. STATION, ZU NeAPEL," VOL. 2, PART 1, 1880. 



(Concluded.) 



Dr. Mayer meets the difficulty in the shrinking of the larger 

 objects, by making an insertion with a fine pair of scissors in an 

 unimportant part of the body cavitVj so as to allow the oil to enter at 

 once. This answers yery well, and can be used with very small 

 objects, such as j4uricularia and other larvse, if a fine flattened 

 needle be used. If this should fail, and especially when the number 

 of objects to be transferred to balsam is large, the alcohol may be 

 supplanted gradually. Dr. Mayer has thus prepared' very young 

 larva of Echinoderms. The specimens were taken up in a capillary 

 tube, with the surrounding alcohol, and then placed in a tube, with a 

 drop of oil of cloves at the bottom. After the lapse of half-a-day the 

 larvae, which at first swam on the top of the oil, had got to the bottom 

 of it, and could be easily removed again by the same tube. Objects 

 may be left in oil of cloves for months without any apparent detriment. 



Recently Kleinenberg has recommended the use of Coloplioniim 

 instead of Canada balsam. The solution in absolute alcohol is not 

 suitable, as under certain circumstances the finished preparations will 

 show large bundles of crystals. Turpentine should be used as a 

 solvent ; this, however, has the disadvantage that the preparations 

 dry very slowly. The solution in chloroform seems to answer well, 

 but must be filtered before use. Further experience is required with 

 this medium before its use can be strongly recommended. 



A solution of Sandarac in absolute alcohol, which at first appeared 

 to answer well, has not, on further trial, proved satisfactory. 



Methods of Dissection. — The dissection of single organs by means 

 of needles, scissors, (fee, from fresh animals, is generally carried on 

 in weak alcohol, or an aqueous solution of chromic acid. By this 

 process a certain maceration of all the tissues takes place, so that 

 afterwards it is often impossible to be certain of the histological 

 character of the respective parts. With large objects which cannot 

 be preserved whole, it is as well to carry on the dissection in picro- 

 sulphuric acid, regardless of the damage done to the cutting 

 instrument. The fluid should be changed as soon as it gets thick, 

 and the preparations well washed in alcohol afterwards. If it is 

 desired to harden the tissues, chromic acid may be added to the picro- 

 sulphuric acid. The preparations thus obtained of parts of large 



