tegrated without a considerable number of operations, and the possible consequences of such repeated manoeuvrings in the bladder are sufficient to make us incline to the side of lithotomy.

On the indications connected with the form and position of calculi, little need be said. The stone must be seized and fixed before it can be crushed, and there may be some difficulty in grasping a very flat calculus; but with our curved instruments this difficulty is, I believe, very rarely insurmountable.

The condition of the urinary organs, is the next point to be examined in reference to the indications of lithotrity. It is almost unnecessary to say that a healthy state of the urinary organs is the most favourable condition that can present itself in connexion with lithotrity, while, on the other hand, any serious organic disease of the bladder or its appendages contraindicates the operation. Still, few calculous patients are altogether free from some disorder of the urinary apparatus, and many affections of the bladder merely influence the results of lithotrity without absolutely contraindicating it. Hence it is a matter of great importance (although much easier in theory than in practice) to ascertain what morbid conditions of the genito-urinary system are incompatible with the safe and successful application of lithotrity.

The state of the prostate first demands our attention, for it may influence the simple introduction of the instruments, as well as the operation and its results. In a former chapter, I described the different morbid conditions of the prostate which have been found in connexion with vesical calculi; one or both of the lateral lobes

may be increased in size; the middle lobe also may be enlarged, and form a more or less prominent tumour, which projects backwards into the cavity of the bladder. The substance of the gland may be inflamed, its vesical surface may be the seat of ulceration, or, finally, abscesses may exist in the body of the prostate itself.

Partial or total enlargement of the prostate must necessarily cause some deviation of the prostatic portion of the urethra, and thus create a greater or less obstacle to the introduction of instruments. When the enlargement is moderate, we generally succeed in overcoming the obstacle by depressing the handle of the instrument a little when its point arrives near the pubic arch; and a greater degree of enlargement will require a corresponding amount of depression. The curve of the instrument is thus carried over the enlarged gland without any considerable difficulty, but great care and gentleness are indispensable; the operator must avoid dragging the parts too much, which would excite severe pain; and he must also avoid injuring or perhaps lacerating the superior surface of the prostatic portion of the canal, which might occur if the handle of the instrument be depressed too low.

It is easy to understand how any considerable enlargement of the prostate-particularly of its middle lobemust diminish the cavity of the bladder, and thus impede the free play of instruments within this organ. The tumefaction of the middle lobe, which projects backwards, deepens the floor of the bladder, and the calculus is thus often concealed in a kind of artificial cavity; the antero-posterior diameter of the bladder is also more or less altered and prolonged backwards. These

circumstances are calculated to impede the manipulation after the introduction of the lithotrite. The rotation of the open blades is circumscribed, and the seizing the calculus is thus rendered more difficult. Indeed, when the middle lobe of the prostate is greatly enlarged, it may be impossible to grasp the stone without executing a movement of complete rotation, and turning the concave surface of the instrument against the gland.

The same disposition of parts which prevents us from seizing the calculus with facility must also impede the ready discharge of fragments from the bladder; and this is an objection of great importance.

Fig. 60.

Fig. 60.-A calculus in the prostatic portion of the urethra, and a second one in the depression behind the prostate. The point of the sound passes over both.

Enlargement of the prostate gland is an unfavourable circumstance for the performance of lithotrity, but it is no absolute contra-indication, as some writers assert, nor, on the other hand, is it to be regarded with indif

ference. The main points to be ascertained, before deciding on the propriety of operating, are the nature and extent of the obstacles which the enlargement of the gland may oppose. These can only be determined by a very careful examination of the patient with the sound and finger. By introducing the finger into the rectum, &c., we must obtain as correct a notion as possible relative to the size of the gland; we must ascertain whether the whole or a part only of the prostate be enlarged, and if a part, whether it be the lateral or middle lobe; we must observe how the urethra has become altered, whether to the right, or left, or upwards. We must endeavour to find out, if possible, how far the middle lobe of the prostate projects backwards into the cavity of the

bladder, and what is the form or extent of the pouch in the floor of the bladder on which the calculus rests. All this requires dexterity and judgment, but it is necessary to obtain such preliminary knowledge, unless we prefer going to work in the dark; and it has been clearly established that the want of success, in many cases of lithotrity, mainly depends on the operator having neglected to ascertain beforehand certain conditions, on an acquaintance with which the ultimate success of the operation intimately depends.

Let us now suppose that on examination we have discovered some enlargement of the prostate, but not to any considerable extent. Here we may proceed to operate, provided the stone be of moderate size, and the organs not very sensitive. On the other hand, when the increased size of the prostate is considerable, and the bladder contains several calculi or a single large one, lithotrity is contra-indicated.

Any serious disorder of the urinary organs co-existing with enlargement of the prostate, should, in my opinion, be also regarded as a contra-indication. Thus the neck of the bladder is often very irritable in cases of the kind now under consideration; there may be chronic catarrh of the bladder, or that organ may be in a state of atony, &c.

Lithotrity has been successfully employed in spite of these complications; but whenever they exist in conjunction with enlargement of the prostate, I should, for my part, prefer having recourse to lithotomy. These principles may also be applied to cases in which the bar-like ridge crosses the neck of the bladder. Such an obstacle exercises nearly the same influence as enlarge