Part 48

ARTICLE FIRST.

GENERAL REMARKS UPON THE CIRCULATION.

I. Division of the Circulation.

Circulation of red blood.—General organs.—Direction.

Circulation of black blood.—General organs.—Direction.

Difference of the two circulations.—Their separation is complete.—Opposition of the lungs to all the parts.

General mechanical phenomena of the two circulations.—Conical form of the circulatory apparatus.—There are two cones for each circulation.—The heart is placed at their union as a double agent of impulse.—Its inequality in this respect. 275

II. Reflections upon the General Uses of the Circulation.

General uses of the circulation of the red blood.—It furnishes the materials of secretion, exhalation, absorption, &c.—All the great phenomena of the economy are derived from it.

General uses of the circulation of black blood.—It repairs the losses made by the preceding, by the substances which it receives.—General and opposite attributes of the two—sanguineous systems. 282

ARTICLE SECOND.

SITUATION, FORMS, AND GENERAL ARRANGEMENT OF THE VASCULAR SYSTEM WITH RED BLOOD.

Of the two portions of this system.—Of their union.—Position of the agent of impulse compared to the whole body. 285

I. Origin of the Arteries.

Origin of the aorta.—Peculiar anatomical arrangement of this origin. 287

Origin of the trunks, branches, smaller branches, &c.—Number of the arterial divisions.—Angles of origin.—Proportion of the divisions. 288

II. Course of the Arteries.

Course of the trunks and branches.—Their position, relation and direction.—Motions which they communicate. 291

Course of the smaller branches, ramifications, &c.—Position.—Relations.—Curvatures.—These curvatures have no influence upon the motion of the blood.—Proofs.—Uses of these curvatures. 293

Anastomoses of the arteries in their course.—Of the two modes of anastomoses.—Triple mode of those in which two equal trunks terminate.—Anastomoses with unequal trunks.—General remarks upon anastomoses. 296

Forms of the arteries in their course.—In what direction they are conical.—Relation of capacities. 299

III. Termination of the Arteries.

It takes place in the capillary system.—Its varieties according to the organs. 300

ARTICLE THIRD.

ORGANIZATION OF THE VASCULAR SYSTEM WITH RED BLOOD.

I. Texture peculiar to this Organization.

Two principal membranes form it. 301

Peculiar membrane of the arteries.—Thickness.—Colour.—Experiments.—Varieties in the cerebral arteries.—Arterial fibres.—Arrangement of these fibres at the origin of the branches.—Their nature is not muscular.— Their brittleness.—Their resistance.—General consequences. 302