ON PRISON DIET AND DISCIPLINE. 55 



The carbonic acid was also collected in the interval which followed the 

 labour, viz., during three minutes after four minutes' rest, two minutes after 

 ten minutes' rest, and two minutes after thirteen minutes' rest ; and, on the 

 average of the whole, the rate of excretion was above that at rest, viz., 9" 14 

 grains per minute. The quantity of air inspired was also measured at the 

 same periods, and was somewhat less than that which occurred in the previous 

 experiments, viz., 680, 590 and 600 cubic inches, 560 and 540 cubic inches, 

 and 560 and 570 cubic inches per minute. The rate of respiration was 17, 16 

 and 15, and the rate of pulsation at the end of the 15 minutes' rest, was 102 

 per minute. 



Thus the results obtained from inquiries into the quantity of air inspired 

 and of carbonic acid expired during treadwheel-labour closely correspond, 

 and show that at Coklbath-fields the influence of that mode of punishment 

 is to increase the elimination of respiratory products from five to six 

 times during the period of actual labour. 



With the Hard-labour Crank. — The next series of experiments refer to the 

 influence of the crank as an instrument of punishment. This instrument is 

 simply a hand-mill which demands a certain expenditure of force to move 

 the handle, and is described as having a pressure of such a number of pounds 

 as may be requisite to depress the handle from the horizontal to the vertical 

 position. It is not used profitably, and is worked by each prisoner separately 

 in his cell. Experiments have been made at Wandsworth and the New Bailey 

 prisons in the manner already described. 



At Wandsworth the cranks are Appold's patent, and are of superior con- 

 struction. They move with a minimum pressure of 7 lbs., but the pressure 

 required to move them may be increased to 10 or 12 lbs. by a prepared set 

 of weights. The usual number of revolutions which the prisoner must 

 make per day of ten hours, is 13,500; but that number may be reduced at 

 the discretion of the Surgeon. The index is in sight of the prisoner, so that 

 he may ascertain the progress of his work. 



The experiments were made at several periods on two days with 7 lbs. and 

 12 lbs. pressure, and witli varying rates of speed. The rate which was the 

 most natural was forty revolutions per minute, but the prisoners generally 

 performed about thirty per minute. The efl'ect upon the system varied 

 much, both with the pressure and the speed ; but, excepting the rate of 

 pulsation, the very interesting fact was educed, that the total effect of the 

 days work in performing the required number of revolutions was nearly 

 the same, whether the rate teas 30 or 45 jwer minute. With 7 lbs. pressure 

 and 30 revolutions per minute, the quantity of air inspired was somewhat 

 less than double of that at rest, viz., 912|^ cubic inches per minute, with 17 

 respirations and 92 pulsations per minute. Witii the speed increased to 

 45*7 revolutions per minute, the quantities of air inspired were increased 

 to nearly three times that at rest, viz., 1336 cubic inches, with 21*5 re- 

 spirations and 113 pulsations per minute. 



With 12 lbs. pressure and 30 revolutions per minute, the quantity of air 

 inspired was between 2 and 3 times that at rest, viz., 1260 cubic inches ; 

 the rate of respiration 24'7, and the rate of pulsation 11 1*5, per minute. 

 Two experiments gave almost identically the same results, the only difference 

 being 3 pulsations, -4 respiration, and 3 cubic inches of air per minute. 

 With the speed increased to 44*7 revolutions per minute, the average of two 

 experiments gave 1898 cubic inches of air, or about 4 times that at rest, 

 with 24'7 respirations and 150 pulsations per minute. 



The efl'ect of speed in reference to the day's work of 13,500 revolutions 

 may be thus shown : — 



