Ei. Frankland on the Source of Muscular Power. 413 
source of animal heat, here the origin of muscular power! Like the 
piston and cylinde r of a steam-en ngine, the muscle itself i is naa 
a machine for the sesistontation of heat into motion ;_bot 
ous eet of food in commen use, as to their capabilities for 
the production of muscular power. The speaker had eget 
made careful estimations of the calorific value of different mate- 
rials used as food, by the same apparatus and in the same man- 
ner as described above for the determination of the actual energy — 
in muscle, urea, uric acid, and hippuric acid. 
The results are em mbodied i in the following series of tables, but 
assigned to starch, and the other surpassing that of ou | ares 
in the table; but ‘these numbers would obvious isly hav 
utterly fallacious, inasmuch as nadia sawdust nor serail oi 
1s, to any apprec ciable extent, Taieahad. te in the alimentary canal. 
While the force-values experimentally obtained for the different 
articles in these tables must therefore be understood as the max- 
ima assignable to the substances to which they belong, yet it 
must not be forgotten that a large majority of these substances 
appear to be completely digestible under normal circumstances. 
Actual energy developed by one gram of various articles of food when burnt in 
oxygen. 
“ Ae | Heat units. Siren Pesca: 
ame © a 
Der. | epetnigts | 2% [wmantow 
Cheese (Cheshire), ......++.265 6114 4647 2589 1969 240 
3752 10138 1589 429 730 
Apples, 3669 eco | 1554 8 82:0 
Oatmeal, pacts 4004 1696 : 
Flour, ones 8941 . 1669 ar 
Pea-meal, bees 3936 ze 1667 we 
Ground rice, webs 3813 1615 
A : ies 3912 1657 
Bread crumb, 3984 2231 1687 5 
We PERIOD, nba) ta aed oan vo aes Peet 4459 1888 
Beef (lean), 5313 1567 2250 
vi 4514 1314 1912 556 
“ 4343 1980 1839 839 
Mackerel, 606 1789 2568 758 
Whiting, 4520 90 1914 383 
White of egg, 4896 2074 os. 
Hard-boiled egg, ......-++++++- 6321 2383 2 009 
Am. Jour. ea Series, Vou. XLII, No. 126.—Noy., ine 
53 
