GENERAL CONSIDERATIONS. 9 
8. INTERNAL STRUCTURE AND VITAL PHENOMENA OF MAN. 000 
Investigations in reference to the corporeal nature of man are carried on 
under two points of view, one having respect to his anatomy, the other to 
his physiology. By anatomy, is to be understood the structure of the ani- 
mal machine, with the form and constitution of the individual parts; while 
physiology, on the other hand, seeks to explain the office or function which 
each part of the system plays in the animal economy. 
Human Anatomy is divisible, in the first place, into General and Special- 
General Anatomy treats of the minute individual components of the body ; 
their varieties of structure, their peculiarities, and their mode of combina- 
tion; it stands in very close connexion with the chemistry of the human 
body. Special Anatomy refers to the individual organs, teaching their forms, 
magnitudes, positions, and connexions with the other parts of the body. 
4. CONSTITUENTS AND ELEMENTARY TISSUE OF THE HuMAN Bopy. 
The human body consists of solid, liquid, and gaseous substances, so 
intimately united as to be only separable by artificial means. All solid 
particles, for instance, are penetrated by liquid, and these contain gaseous 
in solution. In addition to these, there are cavities in various portions of 
the body, more or less moistened or filled with collections of liquid matter, 
not to speak of the gases contained in the lungs, the intestinal canal, &e. 
The liquids of the human body constitute its principal mass, amounting 
to nearly four fifths of the entire weight. They consist in part of a watery 
matter, generally distributed throughout the body, and containing a little 
albumen and a few salts in solution; partly of nutritious juices, as the 
blood, the lymph, and the chyle; and partly of secretions, which are sepa- 
rated from the blood to be entirely thrown off, or else used for some special 
purpose. ‘Thus we have serous liquids in the cellular tissue, in various closed 
cavities, in the chambers of the eye, and in the inner ear: albuminous are 
found in the synovial membranes and the vitreous humor of the eye: fats 
occur in the cellular tissue and in the marrow of bones: coloring matters in 
the blood, the muscles, and under the skin of certain races. 
All the components of the body may be reduced to fifteen elementary 
constituents, which, however, are not peculiar to it. These are oxygen, 
hydrogen, nitrogen, carbon, sulphur, phosphorus, sodium, chlorine, fluorine, 
potassium, calcium, magnesium, manganese, silicon, and iron. 
Some principal organic combinations of these elements in the human 
body are as follows: tears ; saliva ; crystallin, in the crystalline lens; dbzliary 
resin, biliary sugar (bilin), taurine, bilifulvin, cholesterin, dyslysin, d&e., in 
the bile; wric acid and urea in the urine; caseine, whey, butter, sugar of 
milk, and lactic acid, in milk; mueus; horn, in the epidermis, hair, and 
nails; fibrine in the blood, lymph, chyle, and muscles; albumen in serum, 
in the substance of the brain and nerves, in the muscles, the synovia, the 
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