Many of the data contained in this paper have been already published and submitted to a preliminary process of analysis. From the arrangement then made it was seen that the body-weight exercised two separate, and opposing, influences on the heat production associated with muscular work. A certain steady rate of movement was maintained throughout a long series of experiments, and this was complicated to a different degree, in different groups of experiments, with the performance of different, increasing, amounts of mechanical work. When the heat production was comparatively small, in the case of minimal work performance, it was observed to vary directly with the body-weights of the individual subjects. On the other hand, when larger, this variation was less noticeable, and at a certain stage of increase in the performance of work it was found to have disappeared completely. The fact was very definite, so that in four different groups of experiments arranged in order of reference to rising values of mechanical work the total heat productions measured varied in Group A directly with W
4/3
, in Group B with W
⅔
, in Group C with W
⅓
, and in Group D with W
0
(
loc cit
., p. 111). No attempt was made at the time, other than contained in a statement of suggestions requiring consideration, to explain this phenomenon, for which course, indeed, an excuse might be found in the labour involved in collecting the information, and the even greater labour of dealing similarly with the very extensive series of measurements underlying the published data. To this problem, then, attention is once more directed in the present paper. In the meantime, these original data have been elaborately and excellently examined by Glazebrook and Dye in a manner meriting very considerable interest. Before once more encountering these facts, an explanation of the chief terms utilised may be of advantage, since the mode of experiment and the actual measurements have of necessity to be kept out of sight, and no opportunities arise therefore for an observation of the way in which the measurements are summed to form the total data displayed. Thus, for example, the main data, throughout termed “heat productions,” include frequently a larger quantity of heat than that dissipated from the experimental subject as such, since they include an allowance made for any additional heat stored in his body (an allowance assessed with reference to the rectal temperature), and also include the heat dissipated from the experimental machine (cycle) whenever, and to the same extent as, work is performed upon it by the subject. It is clear that only such sums of the total transformation of energy by the subject are of major physiological interest, as alone equivalent to data obtained from examinations of the exchange of oxygen and carbon dioxide in the concomitant process of respiration, and to data obtained in any other fashion as to the oxidation of material in the body.
The extraordinary athletic performance of leaping gibbons