of Edinburgh , Session 1885—86. 
849 
4. The Duration of the Life of Red Blood Corpuscles, as 
ascertainable by Transfusion. By William Hunter, M.D. 
(Edin.), late President of the Royal Medical Society, 
Edinburgh. 
[Abstract.) 
The question as to the normal duration of the life of red blood 
corpuscles has hitherto been considered more as a matter for specu- 
lative inquiry than for experimental proof. Attempts have from 
time to time been made by various observers to solve it experimen- 
tally, by injecting the blood of one animal into the circulation of 
another, whose blood corpuscles were of different size and shape, 
and then noting how long the foreign blood corpuscles remained 
discoverable in the body of their host. As might have been antici- 
pated, the success of such experiments has not been very striking. 
Marfels and Moleschott, so early as 1856, arrived in this way at 
the conclusion that the normal duration of their life must be a very 
long one, since even after the lapse of months they could still recog- 
nise the corpuscles of the sheep in the circulation of the frog. 
Brown-Sequard, also (1857), made some similar observations, 
with, it must be confessed, somewhat anomalous results : for whilst 
the blood corpuscles of the dog or rabbit were recognisable in the 
blood of fowls a month after injection into the circulation, on 
the other hand, the blood corpuscles of fowls were not to be found 
in the blood of dogs or rabbits even one hour after injection. 
These results were not well reconcilable with each other. The 
latter observation was probably the more correct of the two, since 
as is now known from the experiments of Panum, Landois, Ponfick, 
and others, such a method of investigation, implying as it does the 
use of “dissimilar” blood, i.e ., blood derived from an animal of 
another species, is doomed from the outset to failure, the blood 
corpuscles of such blood when introduced into the body of their 
host always breaking down within a few hours of injection, and in 
larger quantities being directly poisonous to the organism into which 
they are injected. 
It is, therefore, only by transfusion of “ similar ” blood, i.e., blood 
derived from an animal of the same species, that any results bearing 
on the question can be arrived at. That the corpuscles of such 
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