with a view either to pathology or practice, be properly distinguished from it: Such are the diseases sometimes treated of under the names of Carus, Cataphora, Coma, and Lethargus.

1094.] Apoplexy, in all its different degrees, most commonly affects persons advanced in life, and especially those above sixty years of age. It most usually affects persons of large heads and short necks,* persons of a corpulent habit, persons who have passed an indolent life and used a full diet, and especially those who have indulged in frequent intoxication. Men who have long labored under a frequent and copious discharge of blood from the hemorrhoidal vessels, upon either the suppression or spontaneous ceasing of that discharge, are particularly liable to be affected with apoplexy.

1095.] This disease frequently comes, on very suddenly: But in many cases it is preceded by various symptoms, such as frequent fits of giddiness, frequent headachs, a hemorrhagy from the nose, some transitory interruption of seeing and hearing, some false vision and hearing, some transitory degree of numbness or loss of motion in the extremities, some faultering of the tongue in speaking, a loss of memory, a frequent drowsiness, and frequent fits of incubus.

1096.] An attention to these symptoms, and to the predisponent circumstances (1094.) will often enable us to foresee the more violent attacks of this disease.

1097.] When the disease comes on suddenly to a considerable degree, it has been frequently observed to have been immediately induced by violent exercise, by a full and long continued inspiration; by a fit of anger; by much external heat, especially that arising from a crowded assembly of people; by warm bathing; by intoxication; by long stooping with the head down; and by a tight ligature about the neck. The disease has been remarked to make its attacks most frequently in the spring season, and especially when the vernal heat suddenly succeeds to the winter cold.

1098.] The symptoms denoting the presence of this disease will be sufficiently known from the definition given 1093. Although the whole of the body is affected with the loss of sense and motion, it sometimes takes place more upon one side of the body than the other; and in that case the side least affected with palsy is sometimes affected with

Different authors, one of whom is Boerhaave, have supposed that a vertebra is sometimes wanting, the neck consisting only of six instead of seven vericbræ,

convulsions. In this disease there is often a stertorous breathing and this has been said to be a mark of the most violent state of the disease: but it is not always present even in the most complete form or most violent degree of the disease.

1099.] The proximate cause of this disease may be, in general, whatever interrupts the motion of the nervous power from the brain to the muscles, from voluntary motion; or, in so far as sense is affected, whatever interrupts the motion of the nervous power from the sentient extremities of the nerves to the brain.

1100.] Such an interruption of the motions of the nervous power may be occasioned, either by some compression of the origin of the nerves, or by something destroying the mobility of the nervous power. Both these causes we must treat of more particularly; and, first, of that of compression, seemingly the most frequent occasion of apoplexy, and perhaps the occasion of all those apoplexies arising from internal causes.

1101.] The loss of sense and motion in particular parts of the body, may be occasioned by a compression, either of the origin of certain nerves only, or of the same nerves in some part of their course from the brain to the organs of sense and motion. Such cases of partial compression will be more properly considered hereafter; and the affection I am now to treat of being general, it must depend upon a very general compression of the origin of the nerves, or medullary portion of the brain; and therefore, this more general compression only is to be considered here.

1102.] This compression of the origin of the nerves, or medullary portion of the brain, may be produced in differ

ent ways; as,

1. By external violence fracturing and pressing in a part of the cranium.

2. By tumors, sometimes soft, sometimes bony, formed in different parts of the brain, or in its membranes, and becoming of such a bulk as to compress the medullary substance of the brain.

3. By the blood being accumulated in the blood-vessels of the brain, and distending them to such a degree as to compress the medullary portion of the same.

4. By fluids effused in different parts of the brain, or into the cavity of the cranium, and accumulated in such quantity as to occasion the compression we treat of.

And, as to this last, it is to be remarked here, that the fluids effused may be of two kinds; that is, they may be either a portion of the common mass of blood, poured out from red vessels; or a portion of serum or colorless fluid, poured out chiefly by exhalants.

1103.] Of these several causes of compression, the first is not to be considered here, because the removing it does not belong to our province; and the consideration of the second may be omitted, as in most instances it is neither to be discerned nor cured by any means yet known. The third and fourth causes of compression, as they are the most frequent, and are also most properly the subjects of our art, so they are those which deserve our particular attention and we shall therefore endeavor to trace them further back in the series of causes which may produce them.

1104.] Both the states of over distention and of effusion may be produced by whatever increases the afflux and impetus of the blood in the arteries of the head; such as viclent exercise, a violent fit of anger, external heat applied, or any strong pressure upon the descending aorta.

1105.] But both these states of over distention and of effusion, may also and seem to be more frequently produced by causes that operate by preventing the free return of the venous blood from the vessels of the head to the right ventricle of the heart.

1106.] The venous vessels of the brain are of a conformation and distribution so peculiar, as to lead us to believe, that Nature intended to retard the motion of the blood, and accumulate it in these vessels; and therefore, even very small additional resistances to the motion of the blood from these towards the right ventricle of the heart, may still more readily accumulate the blood in them. Such accumulation will most readily happen in advanced life, when the venous system in general is in a plethoric state, and when this plethora takes place especially in the venous vessels of the brain. It will, in like manner, be most apt to occur in persons whose heads are large with respect to the rest of the body; and in persons of a short neck, which is unfavorable to the return of the venous blood from the head. The accumulation of blood in the venous vessels of the brain, will also be most likely to occur in persons of a corpulent habit, either because these may be considered to be in a plethoric state, or because obesity, by occasioning a compression of the blood-vessels in other parts of

the body, more readily fills those of the brain, which are entirely free from any such compression.

1107.] These are the circumstances in the constitution of the body, which, producing a slower motion and return of the venous blood from the vessels of the head, favor an accumulation and distention in them; and we now proceed to mention the several occasional causes, which, in every person, may directly prevent the free return of the blood from the vessels of the head towards the heart. Such are,

1. Stooping down with the head, or other situations of the body in which the head is long kept in a depending state, and in which the gravity of the blood increases the afflux of it by the arteries, and opposes the return of it by the veins.

2. A tight ligature about the neck, which compresses the veins more strongly than the arteries.

3. Any obstruction of a considerable number of the veins carrying the blood from the head, and more especially any considerable obstruction of the ascending vena cava.

4. Any considerable impediment of the free passage of the blood from the veins into the right ventricle of the heart; and it is commonly by this, and the immediately preceding circumstances, that polypous concretions in the cava, or right ventricle, are found to occasion apoplexy.

5. The return of blood from the veins of the head towards the heart, is especially interrupted by every circumstance that produces a more difficult transmission of the blood through the vessels of the lungs. It is well known, that, at the end of every expiration, some interruption is given to the free transmission of the blood through the Jungs; and that this at the same time gives an interruption to the motion of the blood from the veins into the right ventricle of the heart. This clearly appears from that regurgitation of the blood in the veins, which occasions the alternate heaving and subsiding that is perceived in the brain of living animals when the cranium is removed, and which is observed to be synchronous with the alternate motions of respiration. From this we readily perceive, that whatever occasions a difficulty in the transmission of the blood through the lungs, must also interrupt the free return of the venous blood from the vessels of the head; and must therefore favor, and perhaps produce, an accumulation of blood, and an over-distention in these vessels.

It is further to be observed, that as a very full inspira

tion, continued for any length of time, occasions such an interruption of the free transmission of the blood through the lungs, as produces a suffusion of face, and a manifest turgescence of the blood-vessels of the head and neck; so every full and long continued inspiration may occasion an accumulation of blood in the vessels of the head, to a very considerable degree. Thus, as every strong exertion of the muscular force of the body requires, and is attended with, a very full and long continued inspiration, we thence learn why the violent exertions of muscular force have been so often the immediate or exciting causes of apoplexy.

It may also be remarked, that corpulency and obesity seem to operate very much, by occasioning a more diffi cult transmission of the blood through the vessels of the lungs. It appears, that in fat persons, from the compression of the blood vessels in many parts of the body, the vessels of the lungs are thereby kept very full; so that upon the least increase of bodily motion, which sends the blood faster into the lungs, a more frequent and laborious respiration becomes in such persons immediately necessary. This shows, that, in such persons, the blood is not freely transmitted through the lungs ; a circumstance which, as in other instances, must give a constant resistance to the return of blood from the vessels of the head, and therefore favor or occasion an accumulation of blood in them.

Is the motion of the blood in the vessels of the head rendered slower by study, care, and anxiety?

1108.] It is to be observed further, that these several causes (1104.-1107.) of a preternatural fulness in the blood-vessels of the brain, may produce apoplexy in different ways, according as the fulness takes place in the arteries or in the veins.

1109.] Accordingly, first, the increased afflux of blood into the arteries of the brain, and an increased action in these, may either occasion a rupture of their extremities, and thereby an effusion of red blood producing compression; or the same afflux and increased action may occasion an increased exhalation from their extremities, of a serous fluid, which, if not as quickly re-absorbed, may soon accumulate in such quantity as to produce compression.

1110.] Secondly, The plethoric state of the venous vessels of the brain, may operate in three different ways,

1. The fulness of the veins may give such resistance to the blood flowing into them from the arteries, as to deter