246 
An Essay on Fat and Muscle. 
verted by tlie powers of vegetable assimilation into tlie substance 
of the plant, acquire the characteristic properties of organised 
products. Hence, plants can grow at the expense of the elements 
around, where no living substance ever previously existed ; whilst 
animals, on the contrary, can only exist upon matters previously 
organised either by plants or other animals. In their well- 
marked forms, no two things can be conceived to offer a stronger 
contrast than these two great divisions of organised beings, yet the 
naturalist cannot determine, in the animated chain, where the one 
ends or the other begins ; nor can the chemist detect, by his ana- 
lyses, any greater differences in their constituent parts. 
Thus, on the analyses of hay, oats, beans, beef, and potatoes, 
they are found to be composed of the same ultimate elements, dif- 
fering only in their relative proportions : — 
Hay. 
Boussiugault. 
Oats. 
Boussiui^iiult. 
BL'ans. 
l*la\ lair. 
Dried Beef. 
PUiyfair. 
Potatoes. 
Boussingaiilt. 
Carbon .... 
33-47 
41-57 
38-21 
51-82 
12-30 
Hydrogen . , 
4-20 
5 25 
5-84 
7-57 
1-74 
Oxygen . . . 
32-51 
30-10 
33-10 
21-37 
12-04 
Nitrogen. . . 
1-26 
1-80 
5-00 
15-01 
0-32 
7-56 
3-2S 
3-71 
4-23 
1-40 
Water .... 
16-00 
18-00 
14-11 
72-20 
* Out of 100 lbs. of beef muscle there is about 77 per cent, of water, by weight, 
and 23 lbs. of dry matter. 
These elements are not very numerous, the principal of them 
being carbon, oxygen, hydrogen, azote or nitrogen, sulphur, 
phosphorus, together with a few of the alkaline, earthy, and 
metallic bases. A brief knowledge of a few of these elements 
will be found indispensable to be able properly to understand the 
subject of this essay. 
3. Carbon forms from 40 to .50 per cent., by weight, of all 
plants in a dried state, which are cultivated for the food of 
animals. This substance is better known under the name of 
charcoal. 
Oxygen is only found in a gaseous form, and exists in the atmos- 
phere to the amount of 21 per cent, of its bulk: hence it is 
necessary to respiration, and no animal can live in an atmosjihere 
Avhich does not contain a certain portion of uncombined oxygen. 
In respiration it disappears, as will be explained by and bye. It 
exists also in water — every 9 lbs. of this licjuid containing 8 lbs. 
of oxygen; and it forms about one-half, I)y weight, of the bodies 
of all living animals and plants. Indeed, it may be said that it 
forms one-half of the weight of every solid substance we see 
around us — of the solid rocks which compose the crust of the 
