Part 46

Action of certain substances upon the nervous coat; its resistance, &c.—Action of the acids, water, caloric, and the alkalies.—Resistance of the nervous coat.

Medullary substance; its origin, arrangement and proportions.

Comparison between the medullary substance of the brain and the nerves.—Effect of desiccation upon each.—Putrefaction and its phenomena.—Absence of the horny hardening in both.—Action of water upon both.—Action of the acids, the alkalies, neutral salts and the digestive juices.—Difference of the nervous pulp in each part. 190

II. Parts common to the Organization of the Nervous System of Animal Life.

Cellular texture.—It is wanting in the nerves, in the cranium and the spine. Elsewhere it is found between their filaments and cords.—Cellular fat.

Blood vessels.—Their arrangement.—Remarks upon the veins.—Of the blood.—Of the nerves.—Action of this fluid upon them.

Exhalants and Absorbents.—Examination of the opinion upon the exhalation of the nervous coat.—Different observations.

Nerves. 199

ARTICLE THIRD.

PROPERTIES OF THE NERVOUS SYSTEM OF ANIMAL LIFE.

I. Properties of Texture.

They are but very slightly marked.—Remarks upon the nervous distensions. 204

II. Vital Properties.—Properties of Animal Life.

Animal sensibility inherent in the nerves.—Various experiments upon this sensibility.—Remarks upon that of the brain.—Phenomena of the experiments upon the nerves.—Character of the animal nervous sensibility. —Of neuralgias.—Another character of this sensibility.—Experiments.—Consequences. 206

Influence of the nerves upon the animal sensibility of all the organs.—Distinction of the sensations, in this respect, into external and internal.—Subdivision of the external into general and particular.—Part which the nerves perform in each.—Internal sensations.—Uncertainty respecting the nervous influence in sensations.—Differences between animal sensibility and contractility.—Of the nervous atmosphere.—Uncertainty of this opinion. 211

Animal contractility.—Influence of the nerves upon that of the other parts.—How the nerves are the agents of this property.—Different opinions upon the action of the nerves.—Uncertainty of these opinions.—General observations.

Properties of organic life, considered in the nerves.—They are slightly marked.—Increase of the size of the nerves in the affections of some parts.—Various experiments and observations.

Influence of the cerebral nerves upon the organic properties of the other parts.—They are foreign to these properties.—They have not there any known influence, 1st, upon the capillary circulation; 2d, upon exhalation; 3d, upon secretion; 4th, upon absorption; 5th, upon nutrition.—Different proofs of these assertions.—Remarks on the diseases which affect animal life and those which affect organic.—Uncertainty of the term nervous influence. 216

Sympathies.—Sympathies peculiar to the nerves.—Different phenomena of these sympathies.—Sympathies, 1st, between two nerves of the same pair; 2d, between two nerves of the same side; 3d, between the branches of the same pair; 4th, between the nerves and different organs.—Different examples of these sympathies. 224

Influence of the nerves upon the sympathies of the other organs.—Different opinions upon sympathies.—Uncertainty of these opinions.—Division of sympathies founded upon that of the vital properties.—Different influence of the nerves upon each species of sympathy.—Cases in which it is real and those in which it is nothing. 226

III. Properties of Reproduction.

Phenomena of nervous cicatrizations.—Their analogy with other cicatrizations. 233

ARTICLE FOURTH.

DEVELOPMENT OF THE NERVOUS SYSTEM OF ANIMAL LIFE.

I. State of this System in the Fœtus.

It is much developed.—General remarks.—Inactivity of the brain, notwithstanding its development.—Its softness.—Action of the alkalies upon this organ.—The cerebral nerves are developed in proportion.—Peculiar phenomenon of their development.—This phenomenon is opposite to that of the arteries.—Consequence which results from it. 235

II. State of the Nervous System during Growth.

Phenomena at birth.—Influence of the red blood.—Predominance of the nervous system during childhood.—Consequences relative to the sensations, motions and various affections. 240