Page 401. 
64 ON SPHYGMOGRAPHY. 
* Fig. 1. 
TSEREREI 
TAVERRAA TRE TIRAHATT 
IOS 
Another objection is, that there is no firm connection between the 
pulse-spring and the recording lever, so that when the latter is sud- 
denly raised, as by the systolic impulse, the contacts of the lever, inter- 
mediate brasswork, and pulse-spring, are not maintained, and a “ per- 
cussion-rise”’ is seen in the trace. This error is partly obviated by a 
small spring, which presses on the recording lever, and tends to keep 
it in contact with the other moving parts, though this is omitted by 
some, much to the detriment of the instrument. 
Though in the taking of the trace itself, this absence of connec- 
tion between the lever and pulse-spring is disadvantageous, yet in the 
applying and removing of the instrument it is of extreme value, for it 
allows of any amount of pressure being put on the latter, without pro- 
ducing any strain or injurious effect on the former. In practice this 
quality is invaluable, and it is almost impossible to obtain it in any 
construction other than the one under consideration. 
Breguet’s new sphygmograph is very simple and ingenious in prin- 
ciple, and in practice works admirably. As to the older instrument, 
the recording lever is fixed to the body of the apparatus by an axis or 
arbor, but the novelty consists in the manner in which this is brought 
into connection with the pulse-spring. 
The lever is of the third kind, as in the other instrument, but it 
has no steel surface below it for a knife-edge to play on, and it is, 
when not in use, entirely disconnected from the pulse-spring. 
Fig. 2. 
Near the middle of the arbor there is a small circular ring of brass, 
