( 1186 ) 
It seems that with all methods, even with von RECKIANGHAUSEN’s 
arbitrariness of the investigator is by no means excluded. 
It was on purpose that hitherto we did not mention another diffi- 
culty ie. the factor of the arterial wall. 
Usually this factor is entirely left out of account, because it is 
supposed to be = 0. This opinion is chiefly founded on investigations 
made on postmortem arterial walls. Yet in drawing conclusions from 
these investigations one should be very careful. It seems that a short 
time after death the contraction of the arterial wall and at the same 
time its rigidity considerably increase. Investigations made at that 
period have no value for our object. 
On the contrary it seems that the arterial wall is very soft and 
compressible immediately after death, but who will decide if these 
are not already symptoms of mortification > 
And even — who shall decide, if not also in the arterial wall of 
the living animal, whose artery was laid bare, the contraction and 
consequently the compressibility has not changed on account of the 
operation ? 
And if the arterial wall may not be neglected, the determinations 
of the pressure of the blood, as they have hitherto been performed, 
become still less reliable. Is then at the determination of the blood 
pressure according to the method of the greatest oscillations, this 
arterial wall included in the determined blood-pressure, or not? Or 
is perhaps the factor of the arterial wall the cause of the different 
views that are current about the question: which of the great oscil- 
lations are registered at the very moment when the Bp prevails 
in the armlet ? 
With the determinations of the blood-pressure, at all events of the 
maximal one, according to the palpatory method, the arterial wall is 
almost certainly included. 
Could perhaps the comparison of the two methods give us some 
information about the arterial wall? In our opinion the subjectivity 
of the methods is too great. 
After all that has been said, we cannot be surprised that there is 
such a great disagreement among investigators concerning the valuation 
of the influence of the arterial wall. So Leonarp Hir found the 
carotid of a child collapsed by a pressure of 2 mJ/Hq; HerrinGHAM 
and Womack found in their determinations of the compressibility of 
different arteries, 4—18 mMHg, in two cases even 30—34 mM Hy. 
Let us for a moment suppose that the factor of the arterial wall 
is greater than 0, then we can easily understand, why the beginning 
of the great oscillations, and the greatest oscillations do not occur 
