CONDENSATION OF THE BRAIN. SCLEROSIS.
An opposite condition of the brain to any of the varieties of softening is now known as condensation of the brain sub stance, or sclerosis. Sclerosis is a condition extremely to what has been before us when we were treating of disease of the lung known as fibroid disease. It is in fact a condensa tion or hardening of the connective tissue of the nervous struct ure, and the term sclerosis, the same in meaning as sclerotic in relation to the outer coat of the ball of the eye, is therefore ap plied to it. The disease may be localized in the brain, or in the spinal cord, or it may extend through both. It may come on in early life; it may come on in later life; and it may be one of the degenerations of old age. When it is present in children they lapse into imbecility. When it attacks the aged it leads to fail ure, generally, of the vital powers, and to " the second childish ness and mere oblivion." Paralysis agitans. Shaking palsy.
When sclerosis affects the middle-aged it causes persistent motion of the limbs, paralysis agitans, a state of disease in which the sufferer cannot control a persistent agitation or trem bling of the muscles of a part of the body, or even of the whole body, the tremor being attended with gradual loss of muscular power. Paralysis agitans lasts often for many years, ending usu ally in paralysis of some of the muscles of deglutition, or of some other of the muscular structures which are essential to life, but dur ing sleep the agitation ceases altogether. This last fact I was able to observe in a person suffering with the disorder who was under my care for many years. I also found the agitation pass away under anesthesia from chloroform and from methylene bichloride, but it is a slow and always progressive affection towards death.
Apoplexy means a blow or sudden shock by which a person is stricken down. In this country the people speak of it as " a stroke." The suddenness of the attack gives a natural meaning to the expression, for the person affected suddenly falls insensible, but remains warm, often becomes feverish, breathes with noise and difficulty, stertorously, and is sometimes convulsed. The dis ease is rare in persons under the middle stage of life. The symp toms are due always to some sudden pressure made on the brain, or to some sudden arrest of blood through the brain. Usually one of two accidents produces the phenomena. Either a blood vessel of the brain gives way from diseased structure and blood is poured forth into the closed cavity of the skull, sanguineous apo plexy; or, the vessels are obstructed by coagula of blood form ing in the sinuses, the veins which allow the blood to return from the brain; thereupon there is effusion of watery matter from the blood, through the vessels, into the closed cavity; the pressure necessary to cause the phenomena is produced; and, congestive or serous apoplexy is the result.
Of late years we have learned to discriminate another and more limited kind of apoplectic seizure, in which the minute ar terial vessels of some part of the brain become obstructed from coagulation of the fibrine of the blood in them, or from the con veyance into them of minute portions of fibrinous coagulated matter. From these causes there is developed a primary shock, not necessarily passing into complete insensibility, followed by some deficiency of power, or partial paralysis, which may be per manent, but from which there is often a fair recovery.
Sunstroke, sometimes called coup de soled, is a form of apo plexy, attended in its acute representation with all the signs of common congestive apoplectic seizure, and supposed to be due to the direct action of the rays of the sun on the body, during tropi cal weather. There seem to be two varieties; one acute and purely apoplectic, specially affecting plethoric, full-bodied persons, who drink freely of stimulants, and who are prone to congestion of the brain; the other, less acute, in some sense resembling faintness in respect to the symptoms excited, and affecting the prostrated and enfeebled persons. I believe them to be entirely different conditions of disease; but being brought on by the heat of the sun, acting on different constitutions, they are usually con sidered as one, and are incorrectly designated by the same term.