282 
Physiology. — “Comparative researches on young and old erythro- 
cytes.”1) By J. SNAPPER. (Communicated by Prof. H. J. 
HAMBURGER.) 
(Communicated in the meeting of June 29, 1912). 
1. Introduction. 
Of late years various investigations have been carried out with a 
view to ascertain if there are differences between newly formed red 
blood-corpuscles and those which have already circulated for some 
time. For this purpose the blood was examined of animals which 
had been made anaemic in some way or other. Since the loss of 
blood must be made up for by fresh red blood-corpuscles, we may 
depend upon it that the differences existing between the blood before 
and after the artificial anaemia was effected, are caused by the new 
formation of fresh red blood-corpuscles. 
According to recent’) investigations there is a difference between 
new red corpuscles, formed after bleeding, and those formed after 
blood has been lost by injections with blood poisons. This difference 
manifested itself especially when the capacity of resistance of the 
blood-corpuscles was tested by means of hypotonic salt-solutions. 
Whilst the blood-corpuscles of an animal which had been made 
anaemic by poison-injections resisted the hypotonic salt-solution better 
than the blood-corpuscles of a normal animal, this was said not to 
be the case with those animals of which the anaemia had been 
caused by bleeding. 
There are indeed reasons to assume that the regeneration after 
poison-injections will be stronger than after bleedings. Yet it is im- 
probable that the young red blood-corpuscles formed after bleeding, 
should not be distinguished in the same way from the old erythro- 
cytes — though it may be in a slighter degree — as those formed 
after poison-injections. These slighter differences too, may be of im- 
portance, however. As we know, the anaemia effected by injections 
of poison causes the number of blood-corpuscles to decrease so 
strongly that sometimes only 16°/, of the original number are left. 
It is not improbable that after such an extreme loss of blood the 
regeneration may be an abnormal one. On the other hand the pro- 
perties of new red blood-corpuscles, formed after a smaller loss of 
blood will bear a greater resemblance to the properties of young 
red blood-corpuscles formed under physiological conditions. 
1) A more detailed account of these investigations will be published elsewhere. 
2) Iramr and Pratt, Biochem. Zeitschrift, Bd. 18. 
SATTLER, Folia Haemat, 1910. 
