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VARIATIONS IN THE NUMBER OF RED-CORPUSCLES. 341
ished destruction of the blood-corpuscles. A relative increase may be
brought about in different ways. For example, another division of the
blood-corpuscles in the vascular system has been supposed, whereby
the blood-corpuscles accumulate in the capillaries, from which region
the blood has been examined most often (Zuntz). It is also claimed
that a concentration of the blood takes place by increased evaporation
(Grawitz), and finally an increase in the blood-corpuscles has also been
explained by assuming a contraction of the vascular system with the
pressing out of plasma (Bunge, Abderhalden 1
). In connection with
these experiments, it must be remarked that several trustworthy observa-
tions show that under the influence of diminished blood-pressure an
actual increase in the red blood-corpuscles takes place. These and
especially those of Zuntz and his co-workers have shown that under
these conditions an increased activity occurs in the red bone-marrow.
This question is still not clear. Cohnheim and collaborators 2
have
observed in man and dogs, that no essential increase in the blood-corpuscles
and haemoglobin occurs in high altitudes after 12 days. They do not
dispute the action of a continued residence in high altitudes, and they also
do not dispute such an action upon rabbits and mice. The}’ explain
this in these animals by a concentration of the blood due to a loss of water
which is not replaced. In man and dogs on the contrary the loss of
water brought about by perspiration is immediately replaced and the
concentration of the blood prevented and the increase in the number
of blood-corpuscles and of haemoglobin is not observed.
A decrease in the number of red corpuscles occurs in anaemia from differ-
ent causes. Every excessive hemorrhage causes an acute anaemia, or, more
correctly, oligaemia. Even during the hemorrhage, the remaining blood
becomes by diminished secretion and excretion, as also by an abundant
absorption of parenchymous fluid, richer in water, somewhat poorer in
proteins, and strikingly poorer in red blood-corpuscles. The oligaemia
soon passes into an hydraemia. The amount of protein then gradually
increases again; but the re-formation of the red blood-corpuscles is slower,
and after the hydraemia follows also an oligocythaemia. After a little
time the number of blood-corpuscles rises to normal. Inagaki 3
has
made thorough investigations on the changes which the number, volume
and haemoglobin content of the erythrocytes undergo after drawing blood
as well as during regeneration. It is impossible here to enter more in
1
The literature on this subject may be found in Abderhalden, Zeitschr. f. Biologie,
43; van Voornveld, Pfliiger’s Arch., 92.
2
Hohenklima und Bergwanderungen, by N. Zuntz, A. Loewy, Franz Muller, and
W. Caspari, Berlin, 1906; Otto Cohnheim, G. Kreglinger, L. Tobler, O. H. Weber,
Zeitschr. f. physiol. Chem., 78 and Cohnheim, Ergebn. d. Physiologie, 1912, 12.
3
Zeitschr. f. Biol., 49.
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