ON PRISON DIET AND DISCIPLINE. 53 



been determined by Dr. Smith, by experiments made upon liimsclf in Cold- 

 bath-fields, Wandsworth, the New Bailey Sallbrd, and Canterbury prisons. 

 The experiments upon the quantity of air inspired were made by the aid of 

 a spirometer, M'hich was a dry gas-meter with an inverted action and enlarged 

 apertures, and was connected with the body by a mask which enclosed the 

 nose, mouth and chin, and prevented ingress and egress of air, except 

 through pre-arranged valvular openings. This was bound upon the head 

 with straps. The spirometer was adapted to register from 1 to one million 

 cubic inches. The inquiry in reference to the carbonic acid was made by 

 the aid of a double set of the apparatus elsewhere described*. 



With Treadwheel Labour. — The effect of treadwheel labour varies in 

 different prisons with the rapidity of the ascent, and other phenomena. Thus 

 at the Coldbath-fjelds prison the amount of air inspired per minute during 

 two minutes after having been upon the wheel five minutes, and again during 

 two minutes after having been upon the wheel thirteen minutes, was, in 

 various experiments, from five to six times the quantity expired at rest, viz. 

 2900, 2605, 2350, 2350, 2435, 2460, and 2450 cubic inches, giving an 

 average of 2500 cubic inches per minute. 



At the New Bailey, Salford, the average of experiments made upon two 

 days gave only between three and four times the quantity at rest, viz., 1839 

 cubic inches per minute. 



At the Canterbury gaol the amount was even less, and varied from 1607 

 to 1820 cubic inches per minute ; but as the rate of ascent varied greatly at 

 that treadwheel, it was impossible to obtain fair average results. 



The rate of respiration at Coldbath-fields was about double that at rest, 

 viz., 27, 26|, 23, 23^, 24^, 25, and 26 per minute. At the New Bailey it was 

 24 per minute; at Canterbury it was still less, and varied from 21-1 to 24 per 

 minute. The depth of inspiration at Coldbath-fields was from 3 to 4 times 

 that at rest, viz., 107^, 911, 94, loo, 99^, 98|^, and 94^ cubic inches. The 

 rate of pulsation at Coldbath-fields was more than double of that at rest, viz., 

 150, 172, and 168 per minute; at the New Bailey 159, and at Canterbury 

 140 to 158 per minute. That of the prisoners was at the New Bailey from 

 125 to 155 per minute ; and at Canterbury, from 118 to 142 per minute. 



Such was the effect of the labour during the period of exertion ; but in 

 order to determine the full influence it is necessary to refer to the intervening 

 periods of rest also ; and in doing so it will be found that, during the whole 

 period of rest allowed, the functions were never restored to their normal 

 action. 



At Coldbath-fields, after thirteen minutes' rest, the quantity of air inspired 

 was still nearly double of that at rest, viz., 980 and 815 cubic inches per 

 minute ; and at the New Bailey, after four minutes' rest, it was 855 cubic 

 inches. The rate of respiration at Coldbath-fields was reduced to an addi- 

 tion of about 5, viz., 18 J, 15, and 16^ per itiinute, and at the New Bailey 

 to 18 per minute. 



The depth of respiration was nearly one-half greater than during normal 

 rest, viz., 53, 48, and 49 cubic inches at Coldbath-fields. 



The rate of pulsation at Coldbath-fields was one half more than the normal 

 . amount, 110,97, and 120 per minute, whilst at the New Bailey it was reduced 

 to 109 per minute. 



These two sets of inquiries, when conjoined with the knowledge of 

 the prescribed duration of each, enables us to compare the effect of these 

 modes of punishment at the different gaols, notwithstanding the almost un- 



* ' Health and Disease as influenced by tlie Daily Seasonal and other Cvclical Changes in 

 the Human System.' By Edward Smith, M.D., F.R.S. Walton and Maberly. 



