quisite sensibility, which is a provision of nature, for their ready and instantaneous action on the stimulus to pass the urine. It is here that is seated that sensibility which produces the natural call to urine, and here also is the seat of diseased irritations. It will be observed that the orifices of the ureters are not closed by the contraction of the muscular fibres around them. They are defended against the return of the urine by the obliquity of their passage through the coats of the bladder. It is well known that the extremity of the ureter enters through the coats of the bladders obliquely, and that in consequence of this, there is a valvular action in the coats of the bladder which prevents the regurgitation of the urine into the ducts of the kidney. But if we look to the adjoining diagram, and consider the subject, we shall find, that in proportion as the bladder contracts, this obliquity must be diminished; and further, if we reflect that the coat which contracts is on the outside of the oblique passage of the ureter, we shall conclude, that without some counteracting power on the inside of the bladder to draw down the orifice of the ureter, the obliquity of the passage would be lost. These muscles, which I have now described, guard the orifices of the ureters by preserving the obliquity of the passage, and by pulling down the extremities of the ureters according to the degree of the contraction of the bladder generally. B H H Explanation of the Diagram. Let A. represent the circle of the dilated bladder. B. The ureter or duct of the kidney entering the coats of the bladder. B. C. mark the oblique course of the ureter through the coats of the bladder. Let D. represent the contracted bladder, thickened at the same time by its contractions. E. The ureter passing through the coats. The lines F. G. drawn from the centre of the circle will intersect corresponding portions of both circles, and demonstrate how the oblique passage of the ureter through the coats of the dilated bladder becomes more direct in the contracted bladder. The muscles described act in the direction of the line H. and its operation is to draw down the orifice of the ureter C. in proportion as the bladder contracts; by which means the obliquity of the passage is preserved. VOL. V. 2 X No. 19. D The membrane which covers these muscles is the seat of that sense which calls the muscular coat of the bladder into action. Of this we may be sensible in passing the bougie, and still more in passing the urethra sound. As the instrument is passed down the urethra, there is a sickening sensation; as it passes the caput gallinaceum, the nature of the pain is changed; and, lastly, in passing it over the surface of the triangular elevation, produced by these muscles, there is experienced the familiar sensation of the call to pass urine. If it were doubted that here, in a particular manner, is seated that sensibility, which calls the bladder into action, the effect of a stone falling upon the part is sufficient proof. When a patient has a stone in the bladder, there is pain and excitement while it rests in this place, and relief when it lodges elsewhere. The reason why this part is possessed of such sensibility, I apprehend to be, that the muscles of the ureters may, as it were, be the first alarmed, in order to guard the mouth of the ureters, and preserve their obliquity during the action of the bladder. Action in Disease. When the sensibility in the seat of these muscles is increased by disease, and the increased sensibility is accompanied with a continual action of the muscles, the prostate gland must suffer unusual excitement. The natural prominence formed by the muscles being directly over the third lobe of the prostate, and their chief attachment being also to this third lobe, we may perceive how it happens that this part is sometimes enlarged without the body of the prostate gland partaking much in the disease. When there is an unusual nisus of the bladder, these muscles are the seat of it; and as their united extremities are attached to the lower and middle portion of the prostate gland, they must, I think, promote the growth of this portion in a direction towards the cavity of the bladder. This will produce the true uvula vesica, the pendulous tumour in the neck of the bladder resembling the uvula of the palate. This tumour hangs into the cavity of the bladder, and falls like a valve upon the orifice of the bladder, proving a most troublesome and dangerous obstruction to the urine. But whilst I state this as an opinion, drawn from the consideration of the parts in their natural state, I must also submit the naked facts. I have, in my collection, two specimens of the disease of the third lobe of the prostate, where these muscles are remarkably strong. I have, on the other hand, some specimens of diseased bladder, where the muscles of the ureters are enlarged; and only in one of these is there a beginning enlargement of the middle lobe of the prostate gland. I have many specimens of bone distorted by the action of the muscles; and many, where, at the attachments of the tendons, the bones are drawn out into spines and tubercles. We may say, such is the effect of the muscles; but though the growth of such spines or tubercles be the effect of the action of the muscles directly, yet these spines will not be formed, unless when the bones are at the same time suffering from disease. So, in considering the action of the muscles of the ureters as influencing the growth of the prostate in a particular direction, I do not imagine that the muscles will do this merely by their mechanical effect. There must be also a disposition to disease in the prostate; and if disease be not present, the irritation of the bladder will continue even till the death of the patient, without affecting the growth of the gland. On the extremities of the ureters, in the diseased action of the bladder, the contraction of these muscles is converted from a salutary influence, to one which aggravates disease. They still close the mouths of the ureters during the action of the bladder; and the action continuing, they cause an accumulation in the ureters and pelvis of the kidney, and influence the kidney itself: thus increasing the extent of the local disorder, and consequently its influence on the constitution. Such consequences as arise from the irritation and action of these muscles, are to be relieved by removing the cause, by assuaging the sensibility of the surface of the tubercle, and by drawing off the urine. When we know that this spot, on the lower part of the orifice of the bladder, is the seat of that irritability which is so distressing, we see that it is practicable to effect it by the use of the bougie. By the introduction of the catheter, the urine is let off without hindrance from the valve: the distressing excitement of the muscles is not perpetuated, and the prostate subsides from its irritation. This practice, though a direct deduction from the examination I have made, is no more than the advice given to us by the best authors. Thus we see that a small tubercle was painted by De Graff, and described by others, but the nature and origin of the tubercle was misconceived. Anatomists were calling it uvula vesica, as if that natural prominence was the same with the tumour of this part of the bladder. We find that the disease called uvula vesica, is no more than that occasioned by the enlargement of the third lobe of the prostate gland. To Mr. Hunter and Mr. Home, we are indebted for a full knowledge of the nature of this disease. It has been objected to Mr. Home, that he is in vain making that important, which the great anatomists of all ages have failed to discover, or have neglected to notice. I have shown that the third lobe of the prostate was known to Morgagni, and that it was a subject of discussion in his day. We have sufficient evidence (even on this very subject) of the difference of a fact being noticed in the elaborate works of Morgagni, and of its being familiarly and practically known to surgeons. The third lobe of the prostate was quite forgotten, the consequence was that we were ignorant of the nature of the most fatal disease of the bladder. It would be disingenuously reserving the circumstance, which drew me to attend to this subject, were I to omit the mention of the late work of Mr. Home, or rather his original paper on the anatomy of the prostate gland. I acknowledge both the merit and the necessity of what he has written: for the observation of Morgagni, and the hint of |