1257 
in the plasma. The volume of the bloodeorpuseles found in this 
way corresponded in a large number of cases to that determined 
in the haematocrite. 
The results of the Austrian investigators have, during the past 
year, been contradicted from different quarters by others who had 
used the same method, but had come to opposite results*). This 
did not surprise us seeing that Farra and Ricurer-Qumrrner had 
used hirudine to obtain the bloodplasma. Before them, however, 
several other investigators had already used hirudine blood and had 
found the bloodcorpusecles to be permeable. 
The explanation of this we thought could be sought in the fact 
that hirudine does not prevent the first phases of coagulation. Only 
after this had been prevented in another way it was found by the 
osmotic experiments that also in the hirudine blood the bloodcor- 
puscles are impermeable to sugar’). If Farra and Ricnter-QuiTTnEr 
in spite of using hirudine blood had obtained the same results, then, 
we thought, it was to be attributed not to the hirudine but to the 
Separation of the plasma and bloodcorpuscles by direct and rapid 
centrifugalisation. Whether, by setting to work in this way, the 
bloodcorpuscles are indeed found to be impermeable to sugar is, 
however, still subject to grave doubt owing to the many failures of 
experiments done with hirudine blood by- others. 
The great theoretical and practical value of the question under 
discussion demands however direct chemical proof which can be 
regarded as being absolute. Also this we think cannot be said of 
the experiments of Fauta and RicHrer-QUITTNER. 
According to our train of thought such direct proofs could be 
given only by examining plasma which was free from bloodcorpus- 
cles and which had been drawn directly from the bloodvessels, or 
had been obtained outside the body from blood which had remained 
perfectly fluid without the addition of a single one of the substances 
which prevent coagulation, for these, after all, do not prevent the 
first phases of coagulation. The amount of sugar in the plasma ought, 
if the bloodecorpuscles were impermeable, to be able to be calculated 
approximately from the total amount of sugar in the blood, and the 
volume of the bloodcorpuscles *). 
1) See f. i Biochem. Zeitschr. 107. 246 and 248. 1920. 
2) BRINKMAN and v. DAM l.c. 
5) We say “approximately” because we want to take for granted for the time 
being that the blood corpuscles have a share in the socalled restreduction. This 
is however very small according to the investigation of R. Ear (Biochem. Zeitschr. 
107, 229, 1920) when determined by the Bang-method which we used. 
81 
Proceedings Royal Acad. Amsterdam. Vol. X XIII. 
