It would not have been very difficult to increase these figures from the large number of recorded cases, but there is nothing in later statistics to invalidate the statement that the corpus striatum, including both its nuclei, but especially the nucleus lentiformis, the optic thalamus, and the white substance in their neighborhood, are the portions of the brain by far the most frequently affected by hemorrhage, and especially by hemorrhages of considerable size.
There is no essential difference in the frequency of hemorrhage on the two sides. It may occur on both sides at once. Hughlings-Jackson says that he saw a patient who escaped with life from the effects of a clot which had paralyzed both sides of the face as well as all four limbs. Charcot and Bouchard give the following localities as containing in decreasing frequency the miliary aneurisms: optic thalami, corpora striata, the convolutions, the protuberance, the cerebellum, the centrum ovale, the middle peduncles of the cerebellum, the cerebral peduncles, and the bulb. The close correspondence of this list with the table of Durand-Fardel is in itself a strong argument in favor of the importance of the miliary aneurisms as the principal factors in determining cerebral hemorrhage.
The arteries supplying the nucleus lenticularis and external capsule are small branches arising chiefly from the middle cerebral a short distance from its origin, with some assistance from the anterior and posterior cerebral. One of the larger of them runs along the outer side of the nucleus lenticularis where it is covered by the external capsule—a disposition which may have something to do with the occurrence of the larger hemorrhages so likely to take place just outside this nucleus and into the substance of the hemispheres.
The arteries of the optic thalamus arise from the posterior communicating or the posterior cerebral. Why these two groups should furnish, as they do, so large a part of cerebral hemorrhages it is impossible to state, unless it be that from their origin so near to the larger trunks before their division they are exposed to more pressure, and hence a greater tendency to form aneurisms. The functional activity of these regions is another possible reason. The largest hemorrhages also seem to spring from these sources, and if a table of large effusions were compiled it would probably show a greater predilection for this locality than even the general one given above, which includes those of all sizes.7
7 A very careful study of the form and size of foci of bleeding arising from the various nutrient arteries of the brain will be found in the well-known elaborate papers of Duret (Archives de Physiologie, 1874).
Before proceeding to a minute account of the symptoms accompanying cerebral hemorrhage, a consideration of the relation between extensive lesions and the most fully-developed clinical phenomena will be of value—in other words, the pathology of hemorrhagic or sanguineous apoplexy. This will naturally demand a reference to the cases where the same symptoms are present with a different lesion.
The most marked symptom, one which is essential to the definition of apoplexy, is the sudden, or more frequently rapid, loss of consciousness, and next, in a great proportion of cases, a unilateral paralysis or paresis. The latter, in many cases, finds a sufficient explanation in the rupture of fibres connecting the motor centres in the brain with the spinal cord; but this does not cover all cases, for it is well known that we may have paralysis without any laceration. In fact, in many cases paralysis may disappear so rapidly as to put aside at once any such explanation. Sufficient pressure upon contracting fibres is entirely competent to arrest their conductivity, and this pressure may be diffused over a considerably wider area than that where total destruction of tissue has taken place. Meningeal hemorrhage, where, of course, no laceration takes place, may be attended by a well-marked hemiplegia when the effusion is wholly or chiefly on one side.
The writer recalls a case of a man, of whose history little or nothing was known, found unconscious with a very distinct difference in the amount of motion to be provoked by irritation of the two sides. The diagnosis naturally inclined to the more common causes of hemiplegia, but the autopsy showed a purulent meningitis of the vertex, with a layer of pus considerably thicker on the side opposed to the paralysis.
A very similar statement may be made in regard to the symptom of unconsciousness, which seldom occurs more rapidly and completely than in cases of meningeal hemorrhage (not from injury), where, of course, there is no question of laceration.
F. Pagenstecher8 succeeded in producing phenomena closely allied to apoplexy by injecting at a known pressure, between the skull and dura mater in dogs, masses of melted wax and tallow. In the first group of cases the result was somnolence, great depression of the psychical capacity, and general muscular weakness. The second group showed, besides the condition of sopor, unilateral paralysis; and the third contained cases in a part of which death followed in a few hours after the setting in of coma, and in another part partial recovery took place after scooping out the waxy mass. The symptoms in these cases are referred to the pressure upon the vessels; and it is stated that in order to destroy life the pressure had to be equal to that of the blood. Convulsions were present in some cases where the pressure was not steady. The temperature showed a notable peculiarity in that, after the initial fall, in which it resembles the course in human apoplexy, it kept on falling in the fatal cases, instead of rapidly rising, as in man. After injection into the brain of animals of sufficient quantities of water to produce great tension of the occipito-atlantoid membrane, Duret9 found the respiration to cease and the heart to be slowed. On tearing the membrane so as to allow the water to escape, respiration began again, and the animals gradually recovered consciousness. Similar effects could, however, be produced by blows on the head.