248 
An Essay on Fat and Muscle. 
Thus, in the azoiised group we have four of the ultimate ele- 
ments, whilst in the non-azotised we have only tlirce, the presence 
or absence of the nitrogen constituting the difference. This dis- 
tinction is a very important one, and must be kept steadily in 
view. The former is only susceptible of being applied to the 
nutrition and renovation of the tissues (2), whilst the non-azotised 
substances are destined either to undergo important changes within 
the body, or to be thrown off from it again, without even forming 
a part of its organised structure. In reference to this, the dis- 
tinction between the organisation of a substance, and the simple 
deposition of it in the midst of an organised tissue, must not be 
lost sight of; for the fatty matters which are derived from plants, 
and become deposited in different parts of the animal body, can- 
not be regarded as ever becoming organised. Till very recently, 
it was believed that vegetable albumen, fi brine, and caseine, dif- 
fered from animal albumen, fibrine, and c-aseine ; but the re- 
searches of Mulder have shown that this opinion was erroneous, 
and Liebig has proved that caseine exists in vegetables, with all 
the characters of that found in milk. Mulder has also shown 
that vegetable albumen, fibrine, and caseine, are all nothing more 
than the modification of one compound, to which he has given 
the name oi proteine, as being the original matter from which all 
those varieties are derived. Vegetable jibrine is a gelatinous sub- 
stance of a green tinge, produced from the newly-e\pressed juices 
of peas, beans, carrots, turnips, beet-root, «Scc. Vegetable albu- 
men is found in many vegetables and seeds, such as cauliflowers, 
asparagus, swede turnips, nuts, almonds, &c. When the clari- 
fied juices of those substances are made to boil, a coagulum is 
formed very similar to the serum of blood, or the white of an 
egg, — this is vegetable albumen, which may be considered as the 
true starling-point of all the animal tissues, as is evident from the 
phenomena of incubation, where all the tissues are derived Irom 
the white and yolk of the egg (which also contains albumen), 
with the aid only of the air, of the oily matter of the yolk, and of 
a. certain projiortion of iron found in the yolk. It is clear from 
this that albumen may pass into fibrine, caseine, membranes, 
horn, hair, feathers, iS:c. Vegetable caseine is found chiefly in the 
seeds of peas, beans, and of other similar leguminous plants ; and 
is identical with the caseine of milk, which is cheese. It differs 
from the two former modifications of ])roleine in that it does not 
coagulate spontaneously like fibrine, nor by heat like albumen, 
but by the action of acids only. 
5. The following table, compiled from one of Professor John- 
ston's (being the analyses of Boussingault, Sprcngel, and Dumas), 
will give the reader a tolejably j usl idea of the proportions of 
