138 MRS. ERNEST HART, 
DUATED CORPUSCLE-COUNTER with WET CHAMBER (Compte- 
Globules a chamhre humide graduée micrometrique!) consists 
of a thick nickel slide, in the centre of which is a circular 
groove enclosing a glass cylinder about a centimeter in dia- 
meter. Outside this groove are three pointed metal screws, 
equidistant from each other. The elevation of these points 
above the surface of the metal slide is exactly} mm. In the 
centre of the glass surface, limited by the groove, are 
drawn the squares, in which the corpuscles are counted. 
These havea side of 3'5 mm., and they are arranged in groups 
of 20, each group having a length of 3;=! mm., and a width 
of »4 =+mm., and an area, therefore, of }x 1=y5 square 
Fie. 2. 
mm. Each group of 20 squares is separated from ad- 
joining groups by a double line (Fig. 2). The peripheral 
1 “Sur les Perfectionnements les plus récents apportés aux Méthodes 
et aux Appareils de Numération des Globules Sanguins, et sur un nouveau 
Compte-Globules,” par L. Malassez, ‘ Arch. de Phy.’ 
