It does not appear that the texture of the ganglions is surrounded by a peculiar membrane. The cellular texture is only condensed in their neighbourhood; it then becomes very consistent, and much contracted around them. It there has the nature of the sub-mucous, the sub-arterial textures, &c.; it never contains fat. There is then truly around the ganglions, as around the arteries, under the mucous surfaces, &c. the two kinds of cellular texture of which we have spoken in treating of the organization of this texture, and which differ so essentially from each other in their nature, and even in their properties. It is the second kind, which is analogous to the sub-arterial texture, &c. which forms the peculiar membrane admitted by some authors.
By examining attentively the interior of the ganglions, we see that there is but very little cellular texture there. I have found this texture constantly destitute of fat; thus the alkalies do not form a saponaceous deposit upon them, as upon the cerebral nerves when plunged in their solution. I have examined many ganglions in this way, on account of the opinion of Scarpa, who believes that these organs are penetrated with this fluid, at least in fat people.
The ganglions receive many blood vessels. These penetrate them from all sides, run first in a kind of cellular covering that surrounds them, then entering their texture, ramify and are lost there in numerous anastomoses, and in continuation with the exhalants that carry nutritive matter. Fine injections show a great quantity of vessels in these little organs. Nutrition supposes exhalants and absorbents there.
III. Properties.
It is difficult to analyze the properties of texture in the ganglions. As to vital properties, they cannot grow, live and be nourished without organic sensibility, and without insensible contractility of the same kind. Animal and sensible organic contractility do not exist there evidently. As to animal sensibility I have observed the following circumstance. As in opening the abdomen of an animal, of a dog, for example, he lives very well for some time, and remains even calm after the first moments of suffering; I have waited for this calm that succeeds the agitation arising from the incision of the abdominal parietes, then laid the semi-lunar ganglion bare, and irritated it powerfully; the animal is not agitated, whilst when I excite a cerebral lumbar nerve, for comparison, he cries out, raises himself up and struggles. In general it appears that the sensibility of the ganglions is infinitely less evident than that of many other organs. Certainly the skin, the mucous system, the medullary, the nervous of animal life, &c. surpass it in this respect.
Our ignorance as to the diseases that have their seat in the ganglions, the distance of those organs from external excitement, prevent our having any data as to their sympathies. I think it very probable, however, that these sympathies take a real part in hysteria, in certain kinds of epilepsy, the paroxysms of which begin, like those of hysteria, by a painful sensation at the epigastric region, in that multitude of affections called nervous, and which the vulgar confound under the name of vapours. One of the most important objects of research in the neuroses, is to determine those that have their particular seat in the nervous cerebral system and those which affect more particularly the system of the ganglions. Place on one side, palsy, hemiplegia, convulsions of infants, tetanus, catalepsy, apoplexy, the greatest part of epilepsies, all the numerous accidents that arise from engorgements, from compressions of the brain from wounds of the head, nervous affections of the sight, hearing, taste, smell, &c. and all the diseases the source of which is evidently in the head; on the other place hysteria, hypochondriasis, melancholia and all that numerous class of affections in which the abdomen and the thorax, the first especially, seem to be the spot in which the evil is seated; you will see that there is an essential difference and that the symptoms have entirely a different character. I do not say that the last kind of nervous diseases affect exclusively the ganglions; for too much obscurity hangs over these affections to pronounce any thing positive as to their seat, or their nature. Undoubtedly even the secretory, circulating, pulmonary organs, &c. can be then particularly affected in their peculiar texture and independently of the nerves they receive; but certainly it is an interesting subject of research, and there is too great a difference in the phenomena of the two orders of affections, not to present differences in their primitive seat. It is difficult to conceive that the system of the ganglions has not a great part in the last order.
That which induces me to think that the difference of the phenomena that the general order of neuroses presents us, arises particularly from the difference of the cerebral nerves and of those of the ganglions, is that their phenomena in a state of health are very different. Hallé has observed very well that the pains that are experienced in the parts in which the nerves coming from the ganglions are distributed, have a peculiar character, and that they do not resemble those that are felt in the parts where the cerebral nerves are sent. Thus the painful sensation that is experienced at the loins in affections of the womb, by vinous injection made into the tunica vaginalis, &c. a sensation that appears to me to arise from the sympathetic influence exercised by the organ affected upon the lumbar ganglions, the pains of the intestines, the burnings at the epigastric region, &c. &c. do not resemble pains of the external parts; they are deep, and go to the heart, as we often say. We know that there are colics essentially nervous, which are certainly independent of every local affection of the serous, mucous, and muscular systems of the intestines. These colics are evidently seated in the nerves of the semi-lunar ganglions, which are spread along the whole course of the abdominal arteries. They are real neuralgias of the nervous system of organic life; now these neuralgias have absolutely nothing in common with the tic douloureux, sciatica, and other neuralgias of the nervous system of animal life. The symptoms, the progress, the duration, &c. every thing is different in these two kinds of affections.
What I have just said upon the injuries of sensation, applies also to those of motion. No kind of comparison can be made between the convulsions of the muscles that receive the nerves of animal life, and the spasmodic and irregular motions which arise in all the muscles that receive nerves from the ganglions. Nothing resembles tetanus in the heart, the intestines, the bladder, &c.
All these considerations establish striking differences between the cerebral nerves and those of the ganglions; differences upon which I can only present approximations, as we have no data as to the functions of the last.