98 



such chamber - - No. 142 - - contains 400 squares, each having an area of l / MO 

 square millimetre. The volume of fluid resting on each square is thus exactly 

 Y-iooo cubic millimetre when a perfectly level cover-glass is laid closely on top 

 of the cell. For counting with low powers we supply cover-glasses 0.6 or 

 0.4 mm thick, but with higher powers (lenses having a focal length of 4, or of 

 less than 4 mm) excessive thickness precludes their use. As, however, it is often 

 necessary to subject specimens to examination under such high powers, we 

 supply cover-glasses having a thickness of 0.18 mm, perfectly plane on one side 

 and having their other side cemented to a stout conical glass cell. 



In conjunction with Hie counting chamber we supply various accurately 

 calibrated mixing pipettes for diluting the blood, &c. (see Directions for Use). 



Fiirther information regarding the variety of forms of the divisions of squares 

 in our counting chambers and the various classes of mixing pipettes are contained 

 in a separate pamphlet dealing with such appliances , copies of which may be 

 obtained on application. 



To facilitate the gradual movement of counting chambers on stands not 

 fkted with a mechanical stage we construct a very simple Movable Stage for 

 the Counting Chamber, by means of which the chamber is slowly moved in 

 one direction by a screw. 



No. 



142: Counting Chamber (cross-line stage micrometer) incl. 



the trvo cove? -glasses, No. 145, in case . . .-_. 

 145: Cover-glasses, 0.4 or 0.6 mm thick, each ... 

 146 : 0.18 mm thick with cemented glass cell 



THOMA's Haemacytometer (Fig. 55) complete, 



in case: 



With mixing pipette for red corpuscles (fig. 55, SM) 



With mixing pipette for ivhite corpuscles 



Prices : 



Marks 75. . 

 0-75- 



Code-words : 



Pedro. 



Peguera. 



Pegujar. 



147: 

 148: 

 149: 



With both pipettes ' . . 36 



150 : Pipette for red corpuscles, each 



151: ,, white ,, 



152: MlESCHER's Haemacytometer zvith specially con- 

 structed mixing pipette, in case 



153: MlESCHER's pipettes, each 



14-. 



Pelafustan. 

 Pelambre. 



154: Movable Stage for the Counting chamber . 



15- Pelamesa. 



