PHYSIOLOGY.

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has also observed, that the blood, which is in continual motion,has a circular course ; that other vessels along with the lacteals areemployed to absorb ; and by means of injection has shewn theroute of the different fluids as clearly in the dead as they couldhave been seen in the living subject. Aided by the microscope,. he has discovered the red globules of the blood, animalculx in thesemen, ami the anastomoses of the arteries and veins; and whenthe microscope could lead him no furth.er, he has had recourse tochemical analysis, and made discoveries equally important, in de-monstrating the bodies which compose the several fluids and thesolids.

A Tahle of the Functions or Properties of Living Bo-dies; ALTERED FROM M. D’AZYR.

1. Digestion. 2. Nutrition. 3. Circulation. 4. Respiration.5. Secretion. 6. Ossification. 7. Generation. 8. Irritability. 9.Sensibility. Every body, in which one or more of these func-tions are observed, is to be considered as possessing organizationand life.

I. Digestion. 1. Living bodies which have one or more sto-machs easily distinguishable from the oesophagus and intestinal ca-nal ;—Man. Quaclruped-. Cetaceous animals. Birds. Crus-taeeous animals. 2. Living bodies which have a stomach distin-guishable only by certain expansions from the oesophagus and in-testinal canal :—Oviparous quadrupeds. Serpents. Cartilaginousfishes. Fishes properly so called. 3. Living bodies which havean alimentary' canal, not distinguishable into oesophagus, stomach,and intestines;—Insects. Worms . Zoophites. 4. Living bo-dies which have neither stomach nor intestines:—Plants.

II. Nutrition. 1. Living bodies whose nutritious juices areabsorbed by vessels beginning from interna! cavities :—Man.Quadrupeds' Cetaceous animals. Birds. Oviparous quadru-peds. Serpents. Cartilaginous fishes. Fishes properly so called.Insects. Crustaceous animals. Worms. 2. Living bodies whosenutritious juices are absorbed by r vessels opening upon the externalsurface:—Plants.

III. Circulation. 1. Living bodies with blood, having a heartwith two ventricles and two auricles:—Man. Quadrupeds. Ce-taceous animals. Birds. 2. Living bodies with blood, with oneventricle divided into several cavities, and two auricles :—Ovi-parous quadrupeds. Serpents. 3. Living bodies with blood,with one ventricle and one auricle:—Cartilaginous fishes. Fishesproperly so called. 2. Living bodies with a whitish fluid ;whose heart is formed of one longitudinal vessel, tuberous, andcontractile, in which there is a whitish fluid instead of blood :—Crustaceous animals. Insects. Worms . In some crustaceousanimals there is observed something resembling a heart. 3. Liv-ing bodies with juices, in which no heart has yet been observed,but only vessels filled with juices of a nature different from that ofblood.—Zoophytes. Plants.

IV. Respiration, i. Living bodies which respire, 1. By lungsfree from all adhesion and spongy :—Man. Quadrupeds. Ceta-ceous animals. 2. By lungs free from all adhesion, vesicular andmuscular:—Oviparous quadrupeds. Serpents. 3. By lungs ad-hering to the ribs, and provided with appendages:—Birds.4. By gills of different forms:—Cartilaginous fishes. Fishes pro-perly so called. Crustaceous animals. 5. By stigmata or holes indifferent rings -.—Insects. Earth-worms. 0. By an opening calledtrachea, or by external fringes:—Aquatic worms. 7. By trachea::

■—Plants, ii. Living bodies in which there have been discoveredneither stigmata nor tracheae :—Polypes.

V. Secretion. Living bodies. There are no bodies in whichsecretions are not carried on.

VI. Ossification, i. Living bodies, whose skeleton is, I. Inter-nal and osseous:—Man. Quadrupeds. Cetaceous animals. Birds.Oviparous quadrupeds. Serpents. Fishes properly so called. 2.Internal and cartilaginous:—Cartilaginous Fishes. 3. Externaland corneous:—Perfect insects. Lithophytes. 4. External andcretaceous:—Crustaceous animals. Shell-fish. Madrepores. Thegreatest part of zoophytes. 5. External and ligneous :—Plants, ii.Living bodies which have no skeleton :—Insects in their first state.Worms . Polypes.

VII. Generation, i. Living bodies, which are 1. Viviparous :n an " Quadrupeds. Cetaceous animals. 2. Oviparous, whether

the evolution of the eggs,takes place within or without the female:

VOL, iv.— no. 176.

—Birds. Oviparous quadrupeds. Serpents. Cartilaginous fishes.Fishes properly so called. Insects. Crustaceous animals. Worm 5 .Plants, ii. Living bodies which propagate by slips :—Worms .Polypes. Plants.

VIII. Irritability. 1. Living bodies which have a body muscu-lar or contractile -.—Greatest part of insects in the first state of theirtransformation. Worms . Polypes. 2. Living bodies which havemuscles covering the skeleton :—Man. -Quadrupeds. Cetaceousanimals. Birds. Oviparous quadrupeds. Serpents. Cartilagi-nous fishes. Fishes properly so called. 3. Living bodies whichhave a skeleton covering the muscles:—Perfect insects. Crusta-ceous animals. 4. Living bodies, which have no muscular power;no spontaneous movements:—Plants.

IX. Sensibility. 1. Living bodies, which have nerves andbrain easily' distinguishable irom the spinal marrow :—Man.Quadrupeds. Cetaceous animals. Birds. Oviparous quadrupeds.Serpents. Cartilaginous fishes. Fishes properly so called. 2.Living bodies, which have nerves and brain scarcely distinguish-able from the spinal marrow :—Insects. Crustaceous animals.Worms. 3. Living bodies, in which there have not yet been dis-covered nerves, or brain, or spinal marrow :—Zoophytes. Plants.The above table, which lias its divisions marked by the functions,and their kinds and varieties by the kinds and varieties of thoseorgans by which they are performed, differs considerably from azoological table. Borrowing its several marks of distinction frominternal characters, it more clearly demonstrates the difference be-tween the mineral, vegetable, and animal, than any system thatattempts to arrange by outward appearances. In order that aitanimal continue in life, it must be allowed respiration; to grow,it must have a supply of food, which is prepared by— Digestion,taken up by— Absorption, distributed by— Circulation, assimi-lated by— Nutrition, and the whole carried on by means of— Se-cretion. These functions are all dependent on a general principleIrritability : by which the system is rendered by stimulants sus-ceptible of— Motion ; accommodates itself to different circum-stances by means of— Habit; alters its shape by successive—Transjonnation ; produces the species by— Generation; the ex-hausted body invigorated by— Sleep ; (ill at last the powers fail,and the consequence is— Death. Accordingly we shall take a viewof the general properties of living bodies.

Of Respiration.

Respiration is that function by which air is brought into the sys-tem, and, by which it is prepared in particular organs, that in somerespect succeed the placenta in the general ceconomy. For, asany interruption of the usual intercourse between the placenta andfoetus in ovo proves soon fatal; so, when that communication na-turally ceases, and the new one succeeds between the lungs ajidexternal air, it is likewise found, that any preternatural interrup-tion of this last is in all living bodies presently attended with va-rious symptoms of increasing languor, and in many with an almostinstantaneous death. So essential is respiration to the system, thatsnails, chameleons, and some other animals, can' live for yearsupon air alone. We have seen a chameleon that lived and wasvigorous for 22 months without any food, and which might havecontinued to live much longer but for an unfortunate bruise by afall. Other phenomena equally demonstrate the importance ofair to the living body. The frog leaps away wanting its heart; itsurvives the loss of the greatest part of its spinal marrow. With-out its head, it lives for some days, and its heart continues to cir-culate its blood. And Borelli found, that eels and serpents,though their bodies be opened, and the whole of their viscera betaken out, are able to move for a day after ; and yet notwith-standing, in all these animals, the life is observed to be suddenlyextinguished when the all-vivifying air is excluded. Even thesmallest insect has died, and the plant lost its vegetative power,when retained for any while in a vacuum. The fish itself, whenplaced under the exhausted receiver, ha^ started anxiously to thesurface of the water in quest of fresh air ; and, finding none, hassunk to the bottom and expired in convulsions. Late discoverieshave shewn that one of the constituent parts of the atmospheric aii,viz. the oxygen gas, is absolutely necessary to support the vitalfunctions. But oxygen gas does not alone enter the lungs. Of100 parts of the atmosphere, but 27 are oxygen gas, is carbonicacid, and 72 are azotic gas. These last, though intended chiefly4 I fi»'