of Edinburgh , Session 1885 - 86 . 
851 
the normal standard is in no way interfered with, and the dura- 
tion of the increase in the number of blood corpuscles after the 
transfusion will, therefore, represent the extent of their duration 
of life. 
This is indeed the case, so far as the tranfused corpuscles are 
concerned ; but the question always arises, how far the duration of 
life of such transplanted blood corpuscles can be taken as a criterion 
of that of normal red blood corpuscles. By transfusion of blood into 
the circulation of a healthy animal, an abnormal condition of the 
blood — a so-called plethora — is for the time being brought aboui, 
which, so far as we know, may very materially influence the duration 
of life of the injected corpuscles. The excess of blood corpuscles thus 
introduced can only be got rid of by a process of increased blood 
destruction on the part of the organism, and thus the transfused 
blood corpuscles are not placed under exactly the same conditions 
as those under which they normally run their life course. In spite, 
however, of these disadvantages, this method enables us to arrive at 
least at an approximate estimate. 
Worm-Miiller found after such transfusions in dogs, that two or 
three days afterwards the number of blood corpuscles present in the 
blood closely corresponded with the number of the original plus the 
injected corpuscles, but that a few days later the blood corpuscles 
began to break down, and by the end of a few weeks at most the 
whole of the injected corpuscles had been removed from the body.- 
The greater the quantity of blood transfused, the longer did this 
process of removal last ; for whilst after the transfusion of 20 to 30 
per cent, of blood the whole of the injected corpuscles were removed 
in the course of a few days, after injection of 60 to 80 per cent, 
their removal was not complete till about the end of the second or 
even the third week. 
According to these results, therefore, the longest duration of life 
of transplanted corpuscles in dogs would be about 2 to 3 weeks. 
Quincke’s more recent observations, also made on dogs, would 
seem to agree with this estimate, the duration of life according to 
him being at least 2 or 3 weeks. His method of investigation, 
however, is open to the objection that the percentage amount of 
haemoglobin in the blood, which he always estimated, does not always 
necessarily correspond with the number of blood corpuscles pre- 
