at crushing. The operation must be abandoned. These are rare and exceptional cases, in which the inability of the bladder to bear the introduction of an instrument, or even tepid water, can only be explained by idiosyncrasy.

The excitement of the bladder often reacts on the kidneys, and gives rise to certain symptoms connected with these organs. Their secretion is augmented by a moderate degree of irritation in the bladder, and the patient passes a considerable quantity of clear, pale urine. When the vesical irritation has been more severe, we observe an opposite effect. The secretion of urine is diminished, perhaps to such a degree as to simulate suppression; the urine is of a deep colour; the patient complains of flying pains in the region of the kidney; and sometimes febrile symptoms, attended with insomnia and great loss of strength, supervene.

Such are the symptoms which may be fairly connected with the operation of lithotrity. We can readily understand that a great variety of other symptoms may arise, should the surgeon persist in operating on a case to which lithotrity is inapplicable; but these do not depend on the operation, and will more properly be examined under the heads of accidents, obstacles, &c., to a consideration of which I now proceed.

The obstacles to the ready performance of the operation naturally come first. What are these? On what do they mainly depend? We can anticipate many of them by simply reflecting on the nature of the operation, and the conditions necessary for its successful performance. Lithotrity, in fact, is made up of the introduction of instruments of a certain size and shape

Enlargement of the prostate not only impedes the easy introduction of the instrument, but its working in the bladder; this we can readily understand, since the same cause is an impediment to the introduction of the catheter. Still we are not to conclude that every degree of prostatic enlargement presents an insuperable obstacle. If this were the case, numerous patients would be deprived of the benefit of lithotrity. Experience has abundantly proved that slight enlargement of the prostate is no contra-indication to the employment of lithotrity. On introducing the instrument some difficulty may be at first experienced, and this must have been great at an early period of lithotrity, when straight instruments only were employed. But the curved lithotrite can generally be introduced, by taking care not to depress the handle too much when the point of the instrument arrives under the arch of the pubes.

On the other hand, any considerable enlargement of the prostate, especially of its middle lobe, which may project backwards into the bladder, must necessarily diminish the cavity of this organ, and therefore impede the free working of the instrument, on which the success of the operation so much depends.

In cases of this kind it would be highly improper to have recourse to the operation without having first ascertained, by careful examination, the degree and nature of the obstacle the surgeon has to contend with. The swelling of the prostate, moreover, has a tendency to deepen the depending part of the bladder behind it, in which the calculus usually lodges; the blades of the lithotrite cannot be opened freely, the movement of rotation downwards is impeded, and the stone cannot

be readily seized. All these points must be taken into consideration; and hence we may conclude, that it is better to abandon the idea of crushing in all cases where the enlargement of the prostate is of such a nature as to render it probable that the operation may be either long or attended with any considerable difficulty. The same observation will apply to fungoid and other tumours of the neck of the bladder or prostate.

Another obstacle, very analogous in its seat and effects to enlargement of the middle lobe of the prostate, arises from the presence of the structure, which Mr. Guthrie has well described under the name of "the bar of the neck of the bladder."

Fig. 50.-Bar-like ridge at the neck of the bladder. The points of the probe show the orifices of the ureters.

This obstruction is generally observed in old persons who have laboured for a considerable time under vesical calculus. It is formed by hypertrophy of the submucous cellular tissue, which rises up like a bar and stretches across the neck of the bladder just behind the middle lobe of the prostate. In some cases the bar contains also a few fibres of hypertrophied muscular tissue. It usually runs horizontally across the neck of

the bladder, or its direction may be a little oblique. The length of the bar varies from one to two inches, and it may rise to a height of half an inch, being sometimes a quarter of an inch in thickness.

The existence of such a barrier as the one now alluded to, must evidently impede the introduction and working of lithotritic instruments in proportion to the extent of the mechanical obstacle. It is also frequently accompanied by hypertrophy of the gland, and the embarrassment of the operator is then increased two

fold.

The lithotrite passes down easily to the neck of the bladder, but there it is suddenly brought up by the dam-like ridge. Hence when the nature of the obstacle has been recognised, the operator must suddenly tilt up the point of the instrument, when he arrives at the impediment, and endeavour to pass over it. He will often succeed in doing this when the bar does not exceed two or three lines in height. When the instrument has been passed into the bladder it can usually be worked without any great difficulty. The movements, however, must give rise to more or less friction against the surface of the ridge, and hence considerable pain, often followed by severe reaction. The presence of this bar-like ridge must likewise prevent the free discharge of detritus, and promote the development of the numerous accidents which may accompany retention of fragments in the bladder.

The condition of the bladder itself may also present certain obstacles which must be taken into account. In many old cases of stone the bladder is hypertrophied, the muscular fibres become abnormally developed and

strong, while, from the long-continuance of the disease, the organ is excessively irritable. The contact of instruments here produces great pain, and excites violent contractions. A moderate quantity of fluid is instantly expelled from the bladder. There is no room, in fact, to manipulate freely in the contracted cavity, and there is much reason to fear that any prolonged attempts may give rise to dangerous symptoms. Here, unless the stone happens to be small and very friable, leading us to conclude that the operation will be terminated in a short time, it is more prudent to abstain from lithotrity. This decision, indeed, is strengthened by other considerations; but these will be noticed when I come to speak of indications.

Another condition of the bladder which presents an insurmountable obstacle to the performance of lithotrity, is that well known under the term "sacculated." Here an accidental cavity is produced by the mucous membrane, which forms a kind of hernial sac through the muscular fibres; and when the calculus becomes engaged in one of these sacs it is said to be encysted. For such unfortunate cases the art of surgery is without resource. They are equally incurable by lithotomy. I suppose, of course, that the calculus is firmly impacted in the sac, and does not leave it; for in some cases the stone passes from time to time into the bladder, and then lithotrity may be employed with advantage.

The size and consistency of the stone are the last points to be noticed. A very large stone nearly filling the bladder cannot be seized by any instrument, and in such a case lithotrity is evidently out of the question; for one of its requisites is, that the calculus should be