In those affections of the spine which are not attended by a paralysed state of the blad der, the urine is not alkaline ; let, however, the power of the bladder be impaired, even to a slight degree, and the quality of the urine will soon suffer. And it is well known that in cases where impediment to the flow of urine from the bladder occurs independently of any para lysis of the organ, as from stricture of the urethra, a similar derangement in the quality of the urine is apt to take place.
It must not, however, be forgotten that chronic disease of the brain or spinal cord is frequently accompanied by phosphatic urine, even when the power of the bladder is unim paired, and that in such urine the addition of a little liquor ammorthe or potassze will cause a more or less copious precipitate of triple phos phate. There can, therefore, be no doubt that the cerebral or spinal lesion affects in some way or other the renal secretion so as to favour the developement of alkaline phosphates in it, and thus to create a tendency to its becoming alkaline. This, however, may arise not from any special influence upon the kidney, but from an undue waste of nervous matter, which would furnish the material for the formation of the phosphatic salt.
A very striking connection between the spinal cord and the kidneys, whereby a dis eased state of the latter organs induces a func tional derangement of the former, is shown by the history of those cases to which the attention of medical men was first called by Mr. Stanley. The patients are more or less completely para plegic, and all the symptoms of disease of the spinal cord exist : but at the same time there exists irritation or actual organic lesion of the kidneys, which, however, may be over looked or attributed to the spinal disease. When the renal disease has been completely removed and the kidneys restored to their normal condition, the paralysis gets well ; but more frequently both the renal disease and the pa raplegia resist all remedial means, and the patients die. On examination, both the brain and spinal cord are found perfectly free from any organic lesion; but distinct evidence of in flammatory or other irritant disease of the kidneys exists.* In a case of this kind which came under my own observation, there was, along with com plete paralysis of sensation and motion in the lower half of the body, excessive hwmaturia, Which had all the characters indicative of renal hemorrhage. From theman's habits and history I suspected that the affection of the kidney had something to do with suppressed gout, and accordingly I used every means to attract gout to the feet. These means were successful, for, no sooner was my patient attacked with an active paroxysm of gout in one great toe than the renal disease began to subside, and the pa mlytic affection disappeared simultaneously.
Itayer, in his valuable work on diseases of the kidneys, relates several cases, which, in addition to those put on record by Mr. Stanley, leave no room to doubt that renal irritation may be propagated to the cord, and may occasion such an amount of disturbance of the functions of that organ as to give rise to paralysis of the lower extremities.
There seems no other mode of explaining these cases than by ascribing them to irritation of the cord excited by irritation of the kidneys, the nerves of the latter organ being the medium through which the renal affection excites the spinal. Yet there is no special connection be tween the nervous system of the kidney and the spinal cord, excepting probably through such tubular fibres as may be found in the renal plexus. These probably run a short course, and their origin in the cord is in close proximity to their distribution in the kidney; and on this account they may be more obnoxious to the influence of irritant disease of the latter organ.
The power which irritation of the cord has to develope erection of the penis may be here noticed as a remarkable instance of the influ ence of that organ over a local circulation. For it is only by assig,ning it to a temporary turgescence of the complex vascular system of the penis that we can explain this erect state. Even in ordinary erection, excited by a stimu lus applied to the. glans, as already pointed out, the influence of the cord is called into action, and the phenomenon is produced by a reflex, or what Dr. M. Hall would call an excito-motor act. Yet, (and here we may no tice how ill-chosen has this term " excito motor " been,) there is in reality no excitation of muscular action but the influence of the stimulus propagated to the spinal cord is extended by a reel( act to the nerves which are distributed to the vessels of the penis, and they, instead of being excited to any contrac tion become rather relaxed, and are thus pre fAred to receive a larger supply of blood ; or by the extension of this excited influence of the cord, the attractive force (vis a fronte) of the capillaries is increased, and thus a larger quantity of blood is attmcted to the organ, and erection takes place. The influence of the nervous system on this act is shown by the most convincing evidence--by the highly sen siti v e state of the organ, especially of the glans; by the large size of its nerves; by the effects of injury or disease affecting the cord imme diately, or by extension from some part of the encephalon ; and lastly, by the experiment of Giinther, who divided the nerves on the dor sum of the penis in a stallion, and thereby destroyed the power of erection, although the vessels were uninjured.