PHILADELPHIA 
Blooa Cesting instruments 
r 
1 ^ 
0 
B 
G 
0.100mm. 
C. Zeiss 
Jena. 
No. 2790 
Haemacytometer, Thoma-Zeiss* For counting the number and ascer- 
taining the percentage of red or white corpuscles in human blood. A standard 
instrument, made by Zeiss-Yena. A measured quantity of blood in a capillary 
pipette is diluted with a normal solution in known proportions ; a drop of this mix- 
ture is deposited upon a small sunken glass platform, and a cover placed thereon. 
This platform is ruled into minute squares, and the number of corpuscles in a num- 
ber of squares are counted with the medium power objective lens of a micro- 
scope. 
2790. Haemacytometer, with pipette for counting red corpuscles, only $10 40 
2792. " " pipettes " " red and white corpuscles, 14 40 
2794. Extra pipettes for red corpuscles, I : loo . . 3 60 
2796. " " white " i : lo . . ■ . . . ... 3 60 
2798. Counting plate, in case 6 00 
2799. Dn R. Friedlande/s Countingf-Chamber for Leucocytes. 
This chamber consists of i6 x i6 squares of 0.3 x 0.3 sq. mm. 
each. The depth of the chamber is 0.222 mm. (see Deutsche 
medicin. Wochenschrift No. 31, July, 1897) 8 00 
2800. Gabritschewsky^s Capillary Pipette, specially adapted for use 
in conjunction with No. 2798 for counting bacteria. With 
divisions at 0.0025, 0.005 to 0.05 c.c. on the capillary tube. 
Total capacity 0.55 c.c. With rubber cap and pinch-screw 
clip 6 00 
The Cover-Glasses for the counting-chambers, as now supplied 
are of two kinds, viz. : the ordinary form of plane polished 
covers of thicknesses of 0.4 and 0.6 mm. respectively and a 
newer form consisting of a plane cover-glass of ordinary 
thickness (about 0.18 mm.) having one side cemented to a 
stout conical glass cell. 
2801. Price of cover-glass of 0.4 or 0.6 mm. thickness 30 
2802. Price of a cover-glass of 0.18 mm. thickness ..... 80 
115 
