E. Frankland on the Source of Muscular Power. 411 
of daily work performed by pedestrians, pile-drivers; porters, 
paviors, &c.; but, as the amount of muscle consumption is cal- 
; xydi 
nic acid, water, and urea. se following are the results ex- 
pressed as in the previous cases 
Hard-worked ee Play fair.) 
Actual energy 
Work performed, required, 
Daily labor eras werk), See 109,496 mks. 218,992 mks. 
Internal wo - - - 80,006 “ 160,012 “ 
189,502 mks. 379,004 mks. 
Actual energy capable of ping produced from 
5:5 oz. (155°92 grams) of flesh-formers con- 
__tained i in the daily food of the la abore 288,140 mks. 
Thus, even under the exes PR IRT conditions of 
these determinations, the actual work performed exceeded that 
which could possibly be produced fheaneh the oxydation of the 
mpeganos constituents of the daily food by more than 30 per 
ve seen, therefore, in He above four sets 3 omnes 
interpreted by the data affor y the combustion of muscle 
and urea in oxygen, that the Ss aaieeieanian of tee alone ca 
be account for more than a small fraction of the sie cower 
developed by animals; in fact, this transformation goes on at a 
rate almost entirely independent o of the amount of muscular aa 
developed. Ifthe mechanical work of an animal be doubled o 
trebled there is no corresponding increase of nitrogen in the o 
cretions ; whilst it was epoted on the other hand by Lawes and 
Gilbert, as early as the year 1854, that sono under the same 
conditions as regarded exercise, had the nt of nitrogen in 
their secretions increased Ewe Mee merely ‘doublin the amount 
of nitrogen in their food. Wh then comes the muscular 
power of animals? What are Aha. Gebetasves which, ‘by their 
oxydation in the body, furnish the actual energy, whereof a part 
is converted into muscular work? In the light of the experi- 
mental results detailed above, can it be doubted that a rge 
proportion of the muscular power developed in the bodies of © 
animals has its origin in the oxydation of non-nityggenous sub- 
stances ft he while the secretion of nitrogen remains nearly 
every augmentation of muscular work, as is shown by the fo 
loan tabulated results of E. Smith’s highly important experi- 
