AMERICAN STANDARD ses 
HAEMACYTOMETERS 
WITH LEVY COUNTING CHAMBER 
AWARDED EDWARD LONGSTRETH MEDAL OF MERIT BY THE FRANKLIN INSTITUTE, 
PHILADELPHIA, 1918 
No. 29983. American Standard Haemacytometer with Levy Counting Chamber 
with Double Neubauer Ruling ; 
At the urgent request of leading haematologists in the U. S., we have discontinued listing as regular 
stock all types of rulings except the Neubauer, which offers all the conveniences for the rapid and ac- 
curate counting of both red and white corpuscles embodied in any other type of ruling. 
We especially recommend the use of the double chamber—suggested by Biirker—in which the 
rectangular strip in the center of the cell is divided by parallel moats and each half provided with a 
Neubauer ruling, so that both red and white counts may be made at the same time without the neces- 
sity of cleaning and refilling the counting chamber. This double type of counting chamber has been 
for several years used in, and recommended by, the clinical laboratories of the Johns Hopkins Medical 
School and has been recently ordered in large quantities by the U. S. Army Medical Department, and 
is rapidly coming into wide use because of its convenience. 
29991. Haemacytometer, American Standard, complete with Levy counting chamber with 
Neubauer ruling, with two cover glasses and one pipette for red and one for white corpuscles, 
in leather case... 2. 6c. es os Ses au us ba ceca + sueueteedellcg Carnet ea 15.00 
29992. Haemacytometer, American Standard, complete as above, with Bureau of Stand- 
ards certificate for counting chamber and both pipettes...................e+00- 20.00 
29983. Haemacytometer, American Standard, complete with Levy counting chamber with 
double Neubauer ruling, with two cover glasses and one pipette for red and one for white 
corpuscles, in leather case...) )2. 5.2... 9% on) eww s ee 18.00 
29984. Haemacytometer, American Standard, complete as above, with Bureau of Stand- 
ards certificate for counting chamber and both pipettes..............2.eseeceee 24.00 
NOTE.—Delivery of outfits 29983 and 29984, double ruling, is subject to some delay because of U.S. 
Government requirements. Delivery of outfits 29991 and 29992, single ruling, made immedi- 
ately upon receipt of order. : 
Send for complete descriptive illustrated pamphlet with prices for 
counting chambers only, pipettes, etc. 
ARTHUR H. THOMAS COMPANY _ 
IMPORTERS—DEALERS—EXPORTERS 
LABORATORY APPARATUS AND REAGENTS 
WEST WASHINGTON SQUARE PHILADELPHIA, U. S. A. 
