1903-4.] Prof. Schafer on Artificial Respiration in Man. 41 
by pinching the nose either by the fingers or by a spring clip. 
The tube which leads from the mouthpiece is forked, and each 
fork passes to a water valve, one for admitting air to the mouth- 
piece, and the other to enable the air which is driven out of the 
chest to pass through on its way to the gasometer. The air which 
is pumped into the gasometer can either be read off at once on a 
scale attached to the instrument, which is graduated in litres and 
tenths of a litre, or it can be . graphically recorded by attaching a 
pen to the moving (ascending) gasometer, allowing this both to 
Fig. 3. — Silvester method. 
register the extent of each movement and also the number of 
respiratory movements per minute upon a blackened drum revolving 
slowly by means of clockwork, and upon which a time tracing is 
also recorded. The tracings so obtained can be afterwards studied 
at leisure. 
Fig. 1 is a photograph showing the arrangement of the apparatus. 
Fig. 2 shows the manner in which any respiratory method is 
investigated by it. The method shown in the photograph is that 
of intermittent pressure upon the lower ribs, with the subject in 
the prone position. 
Figs. 3, 4 and 5 are samples of tracings obtained by this 
method. The ‘ steps 5 upon each curve mark the successive 
