854 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



of the body of the stand is filled with a plate of glass c, the bevelled edges 

 of which are fixed by a strip of metal d. Part of one side is excavated so 

 that a mirror 6 can be fitted in. Beneath one half of the glass plate is a 

 strip of cardboard /, stained in different colours, blue, green, red, black, or 

 white ; Sit g g are two devices drawn with a diamond for exactly centering 



objects on the slide. The use of the mirror is for finding specimens 

 immersed in dark staining fluids. Above the coloured paper, objects can 

 be teased out on grounds suitable to their colour. 



Wax as a Cell Material.* — Mr. J. E. Whitney recommends the sheet 

 wax used for making artificial flowers as a material for cells. The objection 

 usually raised against wax as a dry mount, is that it sweats, and con- 

 sequently the mounted objects become obscured by condensed vapours. 

 The author has met this difficulty by the simple plan of coating the inside 

 of the cell with cement, and his experience of this medium after some 

 years and of some two thousand dry mounts, is that no sweating occurs 

 when this material is properly manipulated. Ordinary sheet wax, the 

 fresher the better, as when old it is brittle, and requires to be warmed, is 

 placed in layers one above the other according to the desired thickness ; 

 and from these layers which are made to adhere by the heat of the hand, 

 rings are punched out. Suitable punches devised by Mr. Whitney were 

 described in the ' Proceedings ' of the American Society of Microscopists 

 for 1884. 



The rings having been punched out are placed on a slide previously 

 warmed and cleaned ; pressure with the finger causing them to adhere to 

 the glass firmly. The turntable upon which the slide had been placed for 

 the previous operation is now revolved, and the inner and outer edges of 

 the ring smoothed down with a penknife. When this is finished, a coating 

 of some transparent cement is laid over the outer and inner surfaces of the 

 ring. The varnish dries in a few hours, but it is better to leave them for 

 a few days well covered up from dust. When the object is placed in the 

 cell and secured by a minute drop of cement, a thin coat of cement is given 

 to the top rim of the cell so that the cover will adhere firmly. The author 

 then usually finishes off his mounts at once by putting on a coat of cement 

 after the cover-glass has been fixed; for that purpose shellac varnish is 



* Proc. Amer. Soc. Micr. 9th Ann. Meeting, 1886, pp. 153-6. 



