We may therefore proceed next to inquire what are the attributes which from direct ob servation and analogical reasoning the uterus may be supposed to derive respectively from the ganglionic and spinal systems, regarded as separate sources of motor power. But here, on account of the intimate manner in which the nerves derived from each of these centres are bound up together, great difficulty arises in distinguishing between the operations of each, and these difficulties can be only in part surmounted.
The circumstances which point more par ticularly to the influence of the ganglionic system will be first considered.
The uterus derives a greater proportionate supply of nerves from the ganglionic than from the spinal system. This appears from the re searches of both Snow Beck and Kilian. The actions therefore of those parts or organs having like endowments, which are in other respects also comparable with the uterus, may be here examined.
Of all organs the heart is that which most nearly resembles the uterus. It constitutes, after the uterus, the largest hollow muscle. Like the uterus, it acts with rhythm, and, in a certain degree, peristaltically. It continues its contractions, with little, if any, interruption, for a long time after its principal cerebro-spinal connections have been destroyed, as by tying the pneumogastric nerves. It continues to contract rhythmically in many animals for a variable time after death, or when cut out of the body. Its contractions are regulated mainly by sympathetic ganglia, while the cerebro-spi nal fibres which it receives serve to establish rela tions between it and other parts.
The uterus exhibits many like peculiarities. It acts with rhythm and peristaltically. It continues these actions, in numerous species of animals, for a variable time after death. Even in the human subject, a post-mortem power of contraction seems to be occasionally retained, as in the case of women whose spon taneous delivery has taken place some time after all evidences of somatic life have ceased.* In these several offices we may conclude that the uterus also, so far as its operations are under the dominion of the nervous system, is, like the heart, chiefly influenced by sympathetic ganglia and nerves.
That this is the case is also further shown by the occurrence of delivery, under circum stances in which all spinal influence appears to be abrogated. The following is an ex ample:I' A woman was attacked with paraplegia in the eighth month of pregnancy. She had
neither sensation nor motion in any part below the umbilicus. No reflex movements what ever could be produced by tickling the soles of the feet. The fmces passed involuntarily, and the urine was drawn off daily. About the ninth month, her medical attendant, when about to pass the catheter, found a full-grown fcetus in the bed (dead). The uterus was con tracted, and the placenta in the vagina. The woman was entirely ignorant of what had occurred. Scanzoni and Chaussier relate simi lar examples of birth taking place notwith standing complete paralysis of the sensitive and motor functions of the lower half of the body. In Chaussier's case the pressure was occasioned by a hydatid cyst which involved the chord on a level with the first dorsal vertebra.* On the other hand, that the uterine move ments are also capable of being influenced by spinal fibres, appears from the following con siderations. Uterine contractions may be ex cited by the application of cold to the general surface of the body, or by placing the child at the breast ; by injecting warm and stimulating fluids into the rectum, and in other like modes.
Again : the uterus, under various circum stances of health and disease, is observed to react upon all or several of the parts just named.
Hence it appears that a mutual relationship is established, by virtue of which the uterus may be either the excitor of actions in these parts, or may through them be itself excited to action. And there can be no doubt that the spinal cord is the 'agent through whose reflex operations these several effects are pro duced.
From this evidence it may be concluded that the double supply of nerves answers dif ferent purposes. That the spinal system fur nishes nerves for the purpose of bringing into harmonious relations all those organs whose cooperation with the uterus is essential or ac cessory to various steps of the reproductive process. While the organ deriving also a simi lar or even larger supply from the ganglionic system, these nerves serve to regulate the functions which the uterus itself is capable of discharging without cooperative aid. In this view the offices of the spinal system, as a system of relations, and of the ganglionic, as a system presiding over the direct acts of the parts which it supplies, may be separately ex hibited. It is doubtless also a chief office of the ganglionic system to regulate and control the action of the blood-vessels with which the uterus is so largely supplied.