Part 50

The two systems are then confounded.—There is but one species of blood.—How the fœtus can live with black blood alone.—Peculiar mode of circulation in the fœtus.—Consequences which result from it.—Insensible change of this mode of circulation.—How it takes place.—Great development of the arteries in the fœtus. 354

II. State of the Vascular System with Red Blood during Growth.

Sudden formation of the red blood at birth.—Changes in the course of this fluid.—Phenomena and causes of these changes.—Predominance of the arteries during youth. 364

III. State of the Vascular System with Red Blood after Growth.

Influence of the genital organs.—Varieties of the influence of the red blood according to the ages. 371

IV. State of the Vascular System with Red Blood during old Age.

Diminution of the arterial ramifications.—The red blood is less abundant.—The arteries are condensed.—Phenomena of the pulse.—Of the pulse in the last moments of life.—Experiments upon this subject. 373

V. Accidental Development of the System with Red Blood.

There are two kinds of it; 1st, Dilatation from an obstacle. 2d, Dilatation from any tumour. 377

VASCULAR SYSTEM WITH BLACK BLOOD.

GENERAL OBSERVATIONS.

ARTICLE FIRST.

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

I. Origin of the Veins.

Manner of this origin.—Two orders of veins. 380

II. Course of the Veins.

Examination of this course on the exterior and the interior. 381

III. Proportion of the capacity of the two systems with Black and Red Blood.

Remarks upon the varieties of venous capacity.—Parallel between the two vascular apparatus with red and black blood in this respect.—General consequences.—The velocity is in an inverse ratio of the capacity, &c. 382

Ramifications, small branches, branches, angles of union, &c.—Forms of the Veins.—In what direction these vessels are conical.—Relations between the branches and their divisions. 388

Anastomoses.—They are very frequent.—Why.—Communication between the external and the internal order.—Consequences.—Different modes of anastomoses.—Their necessity from the numerous obstacles to the course of the blood.—Of these obstacles. 392

IV. Termination of the Veins.

Mode of termination in the heart.—Of the two venous cones, the superior and the inferior.—Of their communication by the azygos. 396

ARTICLE SECOND.

ORGANIZATION OF THE VASCULAR SYSTEM WITH BLACK BLOOD.

I. Texture peculiar to this Organization.

Membrane peculiar to the veins.—Manner of seeing it.—Its longitudinal fibres.—Varieties of these fibres.—Their nature.—Peculiar arrangement of the cerebral sinuses. 399

Common membrane of the black blood.—Its differences from that of the red blood.—More extensibility.—Less thickness.—No disposition to ossify.—Consequences. 403