Part 75

Blood vessels.—Manner in which they are distributed.—Dilatation of the veins in some cases. 293

Nerves.—Mode of their distribution. 294

Absorbents.—Proofs of cutaneous absorption.—Absorption of virus.—Table of this absorption.—Varieties it experiences.—Absorption of medicines.—Experiments.—Character of irregularity of the cutaneous absorptions.—To what this character is owing.—Influence of weakness on this absorption. 294

Exhalants.—Mode of distribution.—Cutaneous exhalations.—Uncertainty of calculations upon this point.—Relation of this exhalation with the secretions.—Relation with the pulmonary exhalation.—Experiment upon this last exhalation.—Remarks upon the causes of many coughs.—Defect of evaporation of the fluid deposited upon the bronchia.—The cutaneous exhalants vary.—Are they under the nervous influence?—This does not appear probable. 299

Sebaceous Glands.—Oily fluid of the skin.—Its quantity.—Its varieties.—Its sources.—We have but few data as it regards the sebaceous glands. 305

ARTICLE THIRD.

PROPERTIES OF THE DERMOID SYSTEM.

I. Properties of Texture.

They are very evident.—They are often less than they seem to be.—Phenomena of extensibility and contractility. 308

II. Vital Properties.

Properties of animal life.—Sensibility.—Of the feeling.—Of the touch.—Its characters.—Its differences from the other senses.—Seat of cutaneous sensibility.—The mode.—Pain peculiar to the skin.—Influence of habit upon this sensibility.—Various reflections.—Diminution of the cutaneous sensibility. 311

Properties of organic life.—They are especially organic sensibility and insensible contractility.—Phenomena over which they preside.—Division of cutaneous diseases.—Excitants of the cutaneous organic sensibility.—Sensible organic contractility is but slightly apparent. 318

Sympathies.—Passive Sympathies.—Different examples and remarks upon the sympathies of heat.—General remarks upon the sensations of heat and cold.—Influence of sympathies upon the sweat. 322

Active Sympathies.—These sympathies are relative to each of the classes of diseases pointed out above.—Various examples.—General remarks. 326

Characters of the vital properties.—First character.—The cutaneous life varies in each region.—Varieties of animal sensibility.—Varieties in the organic properties. 331

Second character.—Intermission in one relation, continuity in another.—The peculiar life of the skin is intermittent as it respects the functions of relation.—Its continuity as it respects its organic functions. 332

Third character.—Influence of sex. 333

Fourth character.—Influence of temperament. 334

ARTICLE FOURTH.

DEVELOPMENT OF THE DERMOID SYSTEM.

I. State of this System in the Fœtus.

A gluey covering in the first periods.—Absence of certain wrinkles in the fœtus.—Laxity of adhesion.—State of the vital properties of the skin of the fœtus.—Its functions at this age. 335

II. State of this System during Growth.

Sudden revolution at birth.—Entrance of the red blood into the skin.—Consequences.—State of the cutaneous vital forces in infancy.—State of the cutaneous texture. 337

III. State of the Dermoid System after Growth.

Increasing proportion of the fibrous substance, and decreasing proportion of the gelatinous.—Remark upon the diseases and affections of the skin. 341

IV. State of the Dermoid System in Old Age.

State of the cutaneous texture.—Phenomena which arise from it.—State of the vital forces.—State of the functions. 344