As bearing upon the exchange of matter in the body in connection with muscular work, and as showing the relationship which exists here between energy exchange and exchange of matter, we may quote a few data relating to the elimination of carbon dioxide; remembering that this substance represents particularly the final oxidation product in the body of carbonaceous materials, such as fat and carbohydrate. The following data, taken from Atwater and Benedict,[38] being results of experiments upon the subject “J. C. W.,” are of value as showing the variations in output of carbon dioxide that may be expected under the conditions described: [38] Loc. cit., pp. 130 and 131. +------------------+---------+---------+-----------+---------+----------+ | | | | | | Extra | | | Rest Ex-| Rest Ex-| Work Ex- | Work Ex-| Severe | | Period. |periments|periments| periments |periments| Work | | | without | with |with Carbo-| with |Experiment| | | Food. | Food. | hydrate |Fat Diet.| with | | | | | Diet. | |Fat Diet. | +------------------+---------+---------+-----------+---------+----------+ | | grams | grams | grams | grams | grams | | 7 A.M. to 1 P.M. | 189.6 | 230.4 | 694.0 | 642.3 | 907.0 | | 1 P.M. to 7 P.M. | 172.6 | 232.0 | 705.6 | 634.8 | 821.3 | | 7 P.M. to 1 A.M. | 167.2 | 196.6 | 260.1 | 230.3 | 842.7 | | 1 A.M. to 7 A.M. | 146.7 | 153.1 | 161.1 | 157.6 | 502.6 | +------------------+---------+---------+-----------+---------+----------+ |Total for 24 hours| 676.1 | 812.1 | 1820.8 | 1665.0 | 3073.6 | +------------------+---------+---------+-----------+---------+----------+