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the diastole was completely closed by the pressure of the armlet, 
but that it could expand itself still fully during the systole of the 
heart, so that, at that moment, the differences in width of the artery 
during the two phases of the heart were greatest. 
And the current view was that the systolic or maximal blood- 
pressure (J/ 4p) in the armlet was reached when the latter showed 
no longer any or hardly any pulsations. It was admitted that then 
the artery, likewise during the systole of the heart, was tightly 
compressed by the armlet, so that it could no longer transfer pulsations 
to the armlet, 
Both these theories are objectionable. 
In the first place the investigators very soon held different views 
about the pulsations of the air in the armlet that indicated that the 
mBp was reached. Originally they were inclined to suppose that 
at the moment, when the maximal pulsations were observed, there 
was mBp in the armlet. Afterwards they thought that the mBp 
in the armlet was reached, when the pulsations in it at increasing 
pressure began to become greater. The pressure of the armlet was 
thought to be at that moment just a little greater than the diastolic 
pressure in the artery. Consequently this artery would be a little 
compressed during the diastole of the heart. From this moment 
therefore the fluctuations of volume in the artery would begin to 
increase, and they would transmit themselves to the air in the armlet 
so that there the fluctuations of volume would likewise increase at 
that moment (v. RECKLINGHAUSEN, ERLANGER, WyBauw). 
We shall revert to this afterwards, but we must now already 
call attention to the fact, that on this point the views are still 
divergent, and that we are still in uncertainty at which pulsations 
the mp in the armlet is in reality reached. 
Moreover the intensity of the pulsations usually increases and 
decreases so imperceptibly, that it is extremely difficult exactly to 
draw the line between large and largest pulsations, and consequently 
too great a margin remains for the subjectivity of the investigator. 
The divergency of views with regard to the MZ Bp. is still greater. 
Soon it appeared that the pulsations in the armlet never ceased 
entirely, not even if the pressure in it was made very strong. Most 
likely this may be attributed to the fact that the artery palpitates 
proximally against the armlet. One tried now to neglect these 
smallest pulsations, and placed the moment of the J//p there, where 
the pulsations began to decrease. But very often also this moment 
cannot be exactly determined. 
These considerations suggested to WyBauw, on the track of OLIVER, 
