ANALYSIS OF 1000 CONSECUTIVE CASES ADMITTED INTO THE SEAMEN'S HOSPITAL, "DREADNOUGHT."
78 a large compound nerve, comprehending the various nervous fibres that originate from it, not only at the place inflamed, but also most of those fibres which proceed from the parts of the cord below the seat of the disease. In consequence of _ this new condition of this nervous centre, the causes of excitation developed in inflammation (pressure by effused liquids, &c.) produce the various phenomena belonging to the three principal kinds of nervous conductors existing in the spinal cord; and
... e spinal cord; and several effects are then produced which are also observed in meningitis and in spinal congestion, owing to pressure upon the spinal nerves. It is interesting to compare, as we will do, myelitis, meningitis, and spinal congestion as regards the phenomena belonging to these three kinds of nerves. 1st. Alterations of ?izoto)-concz'uctors.-Paralysis and cramps are the results of excitations of these conductors. The degree of paralysis in meningitis and in spinal congestion is different from that existing in myelitis, on account of the mode of its production. In myelitis, the number of motor conductors submitted to alterations is much larger, and also the degree of excitation is greater, than in spinal congestion and meningitis; so that both the degree of paralysis and the frequency of cramps are greater in the first than in the last two affections. A pressure upon the spinal nerves in the narrow canals by which they pass out of the spinal cavity is the chief cause of paralysis in cases of meningitis and spinal congestion. This pressure being very variable according to circumstances, great variations exist in the degree of paralysis. The rigid spasm of the muscles of the back in meningitis seems to be due to a reflex action, as in tetanus. 2nd..rllterations of conductors of sensitive impressions.-It is extremely interesting to witness the variety of sensations referred to paralysed parts in cases of myelitis. All the sensations that we may have, in health, in the skin, muscles, and other parts, may then be generated in the cord itself, although they are felt as if they came from the skin, muscles, &c. and it is well known that this fact may be observed even when the skin and other parts are completely deprived of sensibility. In cases of spinal congestion and of meningitis, not complicated with myelitis, the referring of sensations to the skin and other parts is almost null. It might seem strange that a pressure upon nerves of sensibility and movement should be sufficient to produce paralysis, with or without cramps, and not be able to generate those sensations which are so easily produced by a pressure upon the ulnar nerve at the elbow ; but, as I have tried to prove eight years ago, nerve-fibres able to transmit sensitive impressions may or may not be excitable and able to give origin to sensations. In some parts they are excitable, in others they are not; and therefore the absence or slight degree of sensations referred to the skin, muscles, &c., in cases of meningitis, only show that the conductors of sensitive impressions, in their passage out of the spine, where they are subjected to pressure, are not excitable, or, at least, that they have but a slight excitability. 3rd. Alterations of Vaso-motor Nerves.-It is not the place here to insist upon the distinction between the effects of a paralysis and those of an excitation of the vaso-motor nerves.* We will only state that in the three affections we are now comparing, the most important feature is, that there are striking effects of excitation of these nerves. In myelitis, especially, these effects are very marked : the alteration in the urine, the formation of sloughs on the sacrum, the nates, &c., the serous infiltration in the subcutaneous cellular tissue, the rapid atrophy of the paralysed muscles, the dryness of the skin, &c., are phenomena that clearly indicate a great excitation of the vasomotor nerves of the paralysed parts. In cases of spinal congestion and of meningitis, it is not rare to observe these alterations of nutrition, but they are usually to a less marked degree than in myelitis. One of the most interesting effects of excitation of the vaso-motor nerves in myelitis-i, e., the alkalinity of the urine-does not exist in meningitis nor in spinal congestion. It is not rare in these three affections that, near a place where some effect of excitation of the vaso-motor nerves is observed, there are effects of paralysis of these nerves, such as a dilatation of bloodvessels, increased heat, and sometimes an abundant perspiration.