THE NUMBER OF CORPUSCLES. 
149 
X 
collective volume can he directly read off. 1 The estimation can be made 
with a small quantity of blood, and is therefore capable of being used for 
clinical purposes. The average percentage of corpuscles in human 
blood, as obtained by 
these several methods, 
is about 48, or very 
nearly one-half of the 
entire amount of 1)1 1. 
In the horse it is 53 
per cent., in the pig 
43 - 5 per cent., in the 
dog 35-7 per cent., 
and in the ox 32 per 
cent. Hedin obtained 
in himself an average 
percentage total cor- 
puscular volume of 51, 
the greatest differences 
in his own blood being 
54 - 4 and 48 per cent. ; 
but the average for a 
large number of adult 
males was 48 and of 
females 4 3 '3. In chil- 
dren of 6 to 13 years 
the amount was 45 per 
cent. 
Number of corpus- 
cles. — The number of 
red corpuscles in a 
cubic millimetre of 
blood was determined 
by Vierordt and Wel- 
cker to be about 
5,000,000 in adult 
men. There are rather 
fewer in women (about 
4,500,000). Vierordt's 
method consisted in 
diluting the blood with 
a known amount of 
fluid which would pre- 
serve the corpuscles, 
and counting the number in a measured amount of the mixture. The same 
method is still in use, but its application has been greatly simplified in the 
= 2(1 
Fig. 21. — Oliver's apparatus for estimating the number of 
blood corpuscles, a, measuring pipette ; b, dropper to 
contain Hayem's fluid ; c, mixing tube graduated in 
percentages ; d, mode of making the observation. (This 
must be done in a dark room. ) a, b, and c are natural size. 
1 An indirect method, based on the principle of centrifugalising blood with varying 
amounts of salt solution, and determining the organic nitrogen in the supernatant fluid, has 
been introduced by M. andL. Bleibtreu (Arch. f. d. ges. Physiol., Bonn, 1891, Bd. li. S. 151), 
who claim to be able to estimate by its aid, not only the total corpuscular volume, but even 
the average volume and weight of a single blood corpuscle. The method has, however, 
been sharply criticised. (Hamburger, Centralbl. f. Physiol., Leipzig, 1893, Bd. vii. S. 161; 
and Virchoiv's Archir, 1895, Bd. cxli. S. 230 ; Eyckmann, Arch. f. d. ges. Physiol., Bonn, 
1895, Bd. lx. S. 340 ; and Hedin, ibid., S. 360). See further, on the same subject, Lange, 
ibid.', 1S92, Bd. lii. S. 427, and Bleibtreu, ibid., Bd. lx. S. 405. 
