285 
After every bleeding the degree of haemolysis, caused by the 
different salt-solutions, is determined. (Table B). When we also 
represent these values graphically, the curve after every venesection 
is found to have moved in the direction of the lower concentrations. 
(Fig. 2). In the normal animal 80°/, is set free at a concentration of 
0.49 °/, NaCl. After one venesection the same solution causes 66 °/, 
of haemolysis and after 2 venesections only 25°/,. In other words 
whilst only 20°/, of the blood-corpuscles of the normal animal could 
resist a NaCl-solution of 0.49°/,, the composition of the blood is 
changed to such an extent after two venesections, that 75 °/, of the 
blood corpuscles can still bear this concentration. Moreover, the 
haemolysis was complete in the case of the normal animal at 
0.47 °/, NaCl. After two bleedings the same 0.47 °/, NaC! solution 
caused an haemolysis of 40°/, only. Hence there were in the blood 
of the anaemic animal 100 °/, — 40°/,=60°/, blood corpuscles 
which could withstand a less concentrated salt-solution than the most 
resistant blood-corpuscles of the normal animal. These 60°/, are, 
therefore, blood corpuscles which were not met with in the non= 
anaemic animal. They have been newly formed atter the bleeding; 
they are the new blood-corpuscles which are to replace the lost ones. 
Also the young blood-corpuscles, formed after a venesection, have an 
wereased. capacity of resistance *). 
') About the quantity of haemoglobin new erythrocytes contain, more particulars 
might be discovered by counting the number of erythrocytes which remain in 
every concentration. If we compare this with the quantity of haemoglobin set free, 
then it may be decided whether the old erythrocytes contain more or less haemo- 
globin than the new ones. If for instance the old, that is to say the blood corpuscles 
with smaller. resistance contained more haemoglobin, then in the more concentrated 
solutions more haemoglobin would proportionately be set free than in the less 
concentrated ones. Generally speaking, however, the values are found to’ agree 
very well. | 
It is impossible to settle this question conclusively, the method of counting, as 
suggested by Zerss-THOMA, allowing of no closer determination than with an error 
of 50/,. This causes deviations in the agreement of the values. 
By means of the haematokrit-method it can be determined whether there are 
any differences between the volumes of old and new erythrocytes. For this purpose 
the volume of the cells, left after each concentration, was compared with the 
number of erythrocytes left. Though here too, the values were found to agree, the 
method employed in counting gave rise again to important inaccuracies. 
Besides, an equal average volume of new and old blood-corpuscles would be 
the more remarkable since according to unpublished investigations of this institute 
made by HAMBURGER and Kooy, the diameter of new blood corpuscles is greater 
than that of old ones. 
It would follow from this that new and old erythrocytes differ in shape. 
