502 RECORD OF CURRENT RESEARCHES RELATING TO 



above be followed, one will succeed the first time. In case the third 

 evaporation should not give a clear solution it is advisable to begin 

 again with new materials. 



When a clear solution is obtained there should be added to every 

 100 c.c. of the picrocarmine, 25c.c. of strong glycerine, and 10 c.c. 

 of 95 per cent, alcohol ; there will thus be formed a permanent 

 solution that may be kept perfectly clear by filtering once in five or 

 six months.* 



Glycerine-Gelatine for Monnting.f — Herr Otto Brandt, F.E.M.S. 

 and Secretary of the Berlin Microscopical Society, points out that 

 glycerine-gelatine, though known, is not properly appreciated. No 

 other medium offers so many advantages for mounting ; Canada balsam 

 requires a tedious treatment of the object after it comes from the 

 water in which it has been rinsed, such as desiccation, soaking in oil 

 of cloves, and even after three to four months, if handled incautiously, 

 the cover-glass may be displaced ; on the other hand, objects intended 

 for mounting in glycerine-gelatine need no further preparation after 

 being washed, and in a few hours the preparation may be permanently 

 sealed up. 



The little use that has been made of this substance may be 

 accounted for, first, from the method of preparing being little known, 

 and secondly, because the glycerine-gelatine of commerce contains 

 small threads which are difficult to get rid of. Herr Brandt therefore 

 describes his method of preparing and using. 



A quantity of the best white gelatine should be cut up coarsely with 

 the scissors, and laid overnight in a vessel with distilled water, so that 

 it may swell up during the night. In the morning it is taken out, 

 squeezed in the hand, and placed to melt (without adding fresh water) 

 in a glass cup in the water bath ; as soon as the mass has become fluid 

 add to it (stirring continuously) about one and a half times as much 

 glycerine as was taken of the gelatine. 



As the gelatine of commerce is always mixed with particles of dust 

 and minute threads, the filtering of it is a point of vital importance, 

 and this is where many have failed. Swedish filtering paper does not 

 allow the fluid to pass through sufficiently, and flannel produces more 

 threads than before. The following simple apparatus is found effec- 

 tive : A wide-necked bottle is broken in two, and the upper part taken. 

 The neck is stopped with a cork having two holes bored in it. In 

 the first hole a glass tube about 20 cm. long is inserted so as 

 to project a little into the inside of the bottle, and on the outside it is 

 bent sharply to one side and drawn out into a point of about 1^ to 

 2 mm. diameter. In the second hole a funnel-shaped filter is inserted 

 so that the conical part is inside the bottle and the tube projects a few 

 centimetres beyond the cork and the neck of the bottle. The appa- 

 ratus is then placed so that the wide opening of the bottle and of the 



* For three methods of preparing hitherto described see Kanvier's ' Traite' 

 technique de Histologie,' p. 100 ; C. Baber in 'Quart. Journ. Micr. Sci.,' 1874, 

 p. 251 ; Rutherford's ' Practical Histology,' p. 173. 



t ' Zeitschr. f. Mikr.; ii. (1880) p. G9. 



