Temperaments. As the characters of the human species are now fixed with stabili ty, we may sketch the differences which mark individuals. Health, in the expla nation of which all physiology is concern. ed, consists in such a harmony and equi librium of the material fabric of the body, and of its animating powers, as is neces sary for the performance of the various functions. It requires, therefore, fluids rightly prepared ; solids duly formed from these ; the latter thoroughly animat ed by their vital powers; and, lastly, a sound mind in this healthy body. These four principles are constantly acting and re-acting in the human body. The acting act as stimuli on the solids ; which pos sess vital powers, enabling them to re. ceive those stimuli, and to re-act. The connection of the mind and body is not discerned merely in the influence of the will, in what physiologists call voluntary actio»a; since the affections of the body clearly act on the mind in ninny other ways than through the medium of sensual perceptions. The infinitely varied modi fications, which the four principles ad mit of, show immediately with what lati tude our notions concerning health should be formed. Hence arises the dis tinction of temperaments; that is, the dif ferent manner in which the living solid is affected by stimuli, particularly of the mental class, the different aptitude for such impressions, and the greater or less facility with which these stimuli may themselves he excited. There is such great variety of degrees and combinations of temperaments, that a wide field is open for those who wish to employ them selves in dividing and arranging them. The common division is sufficient fbr our purpose ; it comprehends the sanguine °us, which is very easily but slightly af fected by stimuli; the choleric, which is easily and strongly excited ; the melan cholic, which is slowly but deeply mov ed ; and the phlegmatic, which' is the slowest of all in admitting the impres sions of exciting causes. Together with these distinctions, there are numerous differences of bodily formation, of diver sity in the proportion and connection of parts, as well as in the energy relative to certain organs, accompanying each tem perament, which cannot be particulariz ed here, without entering too much into detail.
Each individual has a particular man ner of being, which distinguishes his tem perament from that of every other, to which, notwithstanding, it may bear a ve ry strong resemblance. These indivi dual temperaments, the knowledge of which is of no small importance in the practice of physic, are called idio-syncra sies.
There are many both predisposing and occasional causes, which have an opera tion in producing this diversity of tempe raMents : as hereditary disposition, habit of body, climate, diet, religion, culture, luxury, &c.
For the account of the various races of mankind, see the article Max.
Advanced age and Decay. Cessation of the menses in women, which is occasion ally accompanied by the production of a beard ; an indisposition to venery in the male sex ; and, in both, a peculiar dry ness, and sensible decrease in the vital powers, are the signs of approaching old age.' The body now diminishes, and los es the power it had acquired; the de crease following the same progression as the growth, and occupying about the same space of time, when no accident hastens the approach of death. The whole volume of the body diminishes, the skin wrinkles, particularly in the forehead and tame; the hair turns grey, and organic action becomes languid.
The decay of the body is evidenced by an increasing dulness both of the external and internal senses, necessity of longer sleep, and general torpor of all the func tions. The hair grows white, and falls off, the teeth drop from their sockets, the cartilages ossify, all the organs become hard, and the fibres more dry and con tracted. The head is no longer support ed by the neck, nor can the legs sustain the trunk ; nay, the bones themselves, the foundations of the machine, partake of the general decay. On these pheno mena we may observe, that the animal or exterior life ceases first, the senses fail in succession, and then the functions of the brain cease. The cessation of the loco
motive and vocal powers follows as a ne cessary consequence. Here, then, the old man is dead to all surrounding ob jects, but his organic life still subsists ; so that this state is analogous to that of ute.: rine existence, where the life is nearly of the vegetable kind. Thus, tile body gra dually dies, life is extinguished by suc cessive shades, and death is only the last term in this succession of degrees. We arrive now at the conclusion of physiolo gy; death without disease ; which is the ob ject of all medicine, and the causes of which are necessary and inevitable. It is no more possible for us to avert the fatal term, than to change the laws of nature.
The phenomena of death consist in a coldness of the extremities, gradually mounting to the trunk; dimness of the eye ; feeble, slow, and irregular pulse ; respiration performed at longer intervals, and terminated at last bra strong expira tion. In experiments on animals, a strug gle is observed about the heart, and the right ventricle and auricle are found to survive the opposite cavities for a short time. That death has taken place is shown by coldness of the body, combin ed with rigidity ; flaccidity of the cornea, relaxed state of the anus, lividity of the back, aud a certain cadaverous odour. When all these circumstances are com bined, there will scarcely be any oppor tunity for remarking the uncertainty of the signs of death.
Although the weakness of the thread of life in its early stages, the intemper ance of manhood, the power of disease and of accident, exert such destructive effects on the human race, that out of one thousand children born into the world, not more than seventy-eight die as we have now described, without dis ease ; yet on comparing the longevity of man with that of other mammalia, under nearly similar circumstances, we ;hall be immediately convinced, that, of all the querulous declamations concerning the wretchedness of human life, none is more unjust than the complaint of its short ness.
Putrefaction. As soon as life abandons the organs, they become totally influenc ed by physical laws ; and their compo nent parts have a tendency to separate from each other ; which is stronger in proportion to the multiplicity of their elements. The entire cessation of life is necessary to this change, for life and pu trefaction are two ideas absolutely con tradictory of each other. A mild tempe rature, humidity, and the presence of air, are necessary to putrefaction. Icy cold ness, or great heat, prevent it : the for mer by condensing the parts, the latter by depriving them of moisture. Air is not essential, as bodies will decay in vacuo.
All animal substances exhale at first a musty or cadaverous odour, soften, in crease in size, become heated, change their colour, turn green, blue, and, lastly, a blackish brown. Several gaseous mat ters are at the same time disengaged, among which the ammoniacal is the prin cipal, both on account of its quantity, and because animal matter begins to furnish it, from the instant its alteration commen ces to the period of its complete dissolu tion. Carbonic acid gas is also disengag ed, and forms with the ammoniacal air a fixed salt. Hydrogen, united with phos phorus, sulphur, azote, and carbon, and all things that can result from their re spective combinations, are likewise pro duced.
P utre faction, considered in a philosophi cal point of view, is only the method em ployed by nature to return our organs, that are deprived of life, to a more simple composition, in order that their elements may be employed fur new creations. ( Cir tutus- xierni morns.) Nothing is, there fore, better proved than the metempsy chosis of matter ; whence we may con chide, that this doctrine, like most oldie tenets and fabulous conceptions of anti quity, is only a mysterious veil, dextrous ly interposed between nature and the vul gar by the hand of philosophy.