follow the administration of an ordinary dose of opium. I cannot conceal my belief, indeed, that in many cases where opium has seemed to destroy life when given in very small doses, the “idiosyncrasy” assumed to have been present has consisted in a condition of kidney, during the existence of which uræmia in its acute form might have stood prognosticated, had the earlier symptoms been known.

The acute symptoms of uræmia come on either with coma or convulsion, or both combined. They are usually sudden in their intensity, and are preceded by suppression of urine, or by constipation, or by a chill by which the eliminating function of the skin is suppressed. There is often active convulsion; but I have seen death occur from uræmia without much convulsive movement. Nay, I have seen an animal die from artificial uræmia without active convulsion, though this is an exception. There occasionally will be squinting in the course of the acute paroxysm, but this is not the rule. The state of the pupil varies; but it usually is largely dilated, and is insensible to light, and fixed; the countenance is dusky; the skin is unimpressionable and cool, with short exacerbations of heat.

If the coma be profound, the pulse is slow and intermittent, or irregular in periods. When I say that the pulse is irregular in periods, I mean that, counted over two spaces of time of equal duration, it shows a difference in those two periods. We find the pulse during one minute at 60; we wait a minute and take it again, and although the relation of beat to beat

seems the same, we find that in the course of the second observation five, ten, or even fifteen pulsations have been gained or lost. This form of irregularity of pulse is not peculiar to uræmia, but is common in it, and is inevitably a bad sign. Traced to its cause, it is found to depend on a corresponding irregularity of the respiration, for in nearly all forms of slow narcotic poisoning the heart is obedient to the respiration. The respiration is, from the beginning to the end, irregular and imperfect; there is not dyspnoea, but uncertainty; no obstruction to air, but a destroyed balance in the respiratory move

ments.

Much has been argued as to the condition of the expired air in uræmia; Frerichs has stated that the breath is largely ammoniacal in this state. Other observers have denied the position. In fact, both are right and both are wrong. The true position is simple. In all persons there is an exhalation of ammonia by the breath, varying in amount. In uræmic persons, in their ordinary health, there is, I believe, always an excess of ammonia in the breath; for in them the lungs are supplementing the kidneys. If, then, in any case there be sudden suppression of the excretory power of the kidneys, there may be an excess of ammonia in the breath. I have unmistakably seen examples where this excess was clearly manifested-so clearly that the exhaled vapour gave distinct fumes to the hydrochloric acid rod, and even changed the colour of reddened litmus. On the other hand, there are cases where the very cause of the

development of the acute symptoms lies in the fact that the compensating eliminative function of the lungs has become suppressed: in such state there will be no ammonia found in the breath; it would be a saving clause if the alkali were there.

I have but one word more to say respecting the absolute diagnosis. It relates to the degree of consciousness manifested by uræmic patients in the extreme state.

There are periods when the coma is so profound that nothing arouses the sufferer. There are, again, other times when he arouses of himself, or is quite capable of being aroused, and of speaking or attempting to speak, and of sitting up, and of swallowing foods or medicine, and of acting altogether with a considerable amount of intelligence.

The symptoms above described, taken in all their entirety, are sufficient to give a correct picture of uræmic disease. But it is worthy of remark that there are special symptoms in different cases which, without removing the idea of the general fact that the arrest of the function of the kidneys is the cause of the symptoms altogether, suggest forcibly either that the poison is different in certain instances, or that, being the same in all, it acts variously in different persons, by difference of dose, or by peculiarity of effect on the individual organism. Thus in one case the pupil may be dilated, in another natural in size; in one patient there shall be active convulsions, in another no convulsion whatever; in one there shall be marked derangement of the bowels, in another no intestinal irritation shall be presented; in one there

shall be vomiting as an early symptom, in the next no indication of such an effect. These distinctions, all of import, are nevertheless secondary; since, in every case, they are included in two common symptoms-excretion of albuminous urine, and coma.

Differential Diagnosis. Uræmia simulates in some particulars so many of the diseases in which coma is the leading symptom, that an attempt to enter into the distinctions that mark it off from every analogous disorder would be interminable. In some instances, too, the task would be an exceedingly difficult one, unless considerations relating to the previous existence of albuminuria were admitted into the argument. Thus, for example, the diagnosis between uræmic poisoning and belladonna poisoning is so difficult, that, in a case where the history of the patient was unknown until the occurrence of coma, I for one, after having witnessed both classes of toxæmic disease, would scarcely be able to note a trustworthy sign on which to build a decided opinion. It is obvious, in fact, that the poisons producing the two classes of symptoms are well nigh identical in regard to their effects. Here, therefore, we must rest on the course which the symptoms take, and on such occurrences as the vomiting of suspicious matters, for a guide to diagnosis, rather than on any particular or exclusive symptom.

From epilepsy, uræmia is distinguished by the tendency to diarrhoea, and, above all, by the suppression of urine. Distinctions may also be drawn at the time of the acute paroxysm; for the convulsion of

uræmia is not of the same tonic character as in epilepsy; the asphyxia is not so marked, and the coma is more prolonged.

At one time in the history of medicine, uræmia constituted one of the varieties of coma called generically "apoplexy." The unlearned as yet call uræmia apoplexy. From true cerebral apoplexy, however, uræmia is distinguishable by the facts that the skin is less hot, the stertor less marked, the blowing expiration less frequent, the convulsion more defined, determinate, and paroxysmal, and the suppression of urine more certain.

From poisoning by opium, uræmia is to be distinguished by the following particulars. In uræmia, the pupils are generally dilated; the patient may become quite sensible during the acute attack, and then profoundly relapse; the bowels are often free; the urine is scanty or absent; the breathing is free from stertor; and the convulsions are active. In opium poisoning the pupil is contracted; the patient remains unconscious, or, recovering his consciousness, remains conscious; the breathing is stertorous; the urine free; and the muscles paralytic rather than convulsed.

In fine, in establishing, in a doubtful case, a differential diagnosis between uræmic intoxication and its analogues, we must depend most on the previous history of the patient, and on a correct recollection of the absolute symptoms by which uræmia is manifested. The careful practitioner will then rarely be misled. If, however, a preceding history cannot