215 



September at the sea side. He is set. 42, weighs 196 Ibs,, 

 and is in perfect health. The experiments upon prisoners were 

 made in Coldbath-fields Prison, upon four prisoners in an average 

 state of health, but below the average weight. The object was to 

 determine the effect of treadwheel labour. The prisoners worked 

 the wheel three days, and pursued routine labour on other three 

 days in each week, whilst they rested on the Sunday. Their diet 

 was good, and consisted of 20 oz. of bread, 6 oz. of cooked meat, 

 8 oz. of potatoes, 1 pint of cocoa, and 1 pint of gruel daily, besides a 

 regulated quantity of water, which they drank at prescribed periods. 

 They were under the immediate charge of an officer, and the greatest 

 care was taken to ensure accurate results. On treadwheel days the 

 urine was collected whilst the labour was performed and before 

 breakfast was taken, and at other periods of the day, in a defined 

 manner. The fseces were weighed, and samples of the fseces, urine 

 and food, were kindly analysed by Mr. Manning. During the 

 inquiry certain alterations of diet were made for periods of three 

 days each, such as the administration of extra fat, tea, coffee, and 

 alcohol, and the withdrawal of the chloride of sodium. 



The analyses for urea and chloride of sodium were made by the 

 author, and Liebig's method was adopted. 



Both series comprised more than 1200 analyses for urea and 2000 

 collections of urine. 



The following are the principal results obtained : 



1. The daily excretion of urea varied from 298 grs. to 748'5 grs., 

 but on the average of the year was 519 grs., or 2- 73 grs. to each 

 Ib. of body weight. 



2. The extreme amounts of urine were 24'5 fl. oz. and 92*6 fl. oz., 

 with a total average of 53' 1 fl. oz. daily. The relation to body 

 weight was '28 fl. oz. to each Ib. There were noticeable daily altera- 

 tions in the quantity, or the amounts proceeded in waves or arches, 

 or progressively increased or decreased in a striking manner through 

 a series of days under the influence of meteorological conditions and 

 the statics of the body. The amounts derived from the cycle of the 

 year are almost identical with the average of all recorded inquiries 

 made for short periods, and upon various persons, and show the ex- 

 treme value of including the cycle of the year. 



3. The average quantity of urea in each oz. of urine was 9*4 grs. 



