48 
Proceedings of Royal Society of Edinburgh. [sess. 
pressure upon the hack, the highest of these three numbers may 
be adopted, viz., 254 c.c. per respiration (3300 c.c. per minute). 
This amount, as compared with the tidal air of 450 c.c. per 
respiration, and 5850 c.c. per minute, is obviously inadequate ; and, 
conformably with this, the subject experienced distinct distress 
towards the end of each minute, even when pressure was used. 
In the experiments without pressure, the minutes had to be cut up 
on this account into two periods of half a minute each. 
Although not a great deal of physical exertion is required to 
roll a body half over in this way some 12 or 13 times a minute 
and alternately to press upon the back, yet the labour is much 
greater than that required by the simple pressure method. Such 
efficiency as the method may have depends largely upon the 
alternating pressure, for without this the rolling is quite ineffective. 
The reason why this pressure produces less effect than in the 
method next to be considered appears due to the fact that the 
time taken up by the rolling enables less time to be given to the 
pressure, so that this is almost necessarily inadequately performed 
if the normal rate of respiration is kept up. 
Table YI . — Prone Pressure Method .* — (This is similar to the 
Howard method (intermittent pressure on the lower ribs), 
but the subject is in the prone position.) 
Number of 
Respirations. 
Amount of Air 
in Cubic Cent. 
1st minute, 
12 
6,100 
2nd ,, 
13 
6,800 
3rd ,, 
14 
6,750 
4th 
12 
7,000 
5th 
14 
7,200 
5 minutes, ..... 
65 
33,850 
respirations. 
* 
Remarks . — The rate of respiration was on the average 13, and 
the amount of air exchanged averaged 520 c.c. per respiration, 
* This method is described in a paper communicated by the author to the 
Royal Medical and Chirurgical Society, which was read on December 8th, 1903, 
and will he published in the Med. Chir. Trans. 
