6. And now, sometimes closing this train of symptoms, but more frequently being the first harbinger of another, delirium appears. Delirium is usually first observed when any slight sound rouses the patient from that disturbed slumber which is the only substitute allowed for sleep. The delirium is seldom violent or long-continued, but, when present, is like the talking of a person during sleep in a disturbed dream. This symptom, however, is by no means invariably present, and when it does come, it often postpones its visit to a somewhat later period.
7. The pulse, during all this time, may not be much quicker than in the mild form; and the state of the tongue and of the evacuations does not materially differ.
Such is the train of symptoms when the brain becomes prominently affected. These symptoms continue without intermission, and with little change, for several days. The period of their duration, when only in this degree of violence, is commonly from eight to ten days: when their character is still milder or more subacute, or when they have been mitigated by appropriate remedies, it may be protracted fifteen days.
About this period a remarkable change takes place; an entirely new train of symptoms supervenes, which is different, and which, indeed, presents a striking contrast, according as the patient is destined for life or death.
If it be for life, that sleep, of the long absence of which we have already spoken, returns; and nothing can more truly express its character than its familiar name, “balmy;” and healing is its influence. From two or three hours of such slumber, the patient awakens a new being. Not that the change is at first striking to an inexperienced eye; but there is no fever nurse who does not recognize it in a moment, and it is not long before the patient tells you that he feels it. The febrile uneasiness is now much diminished: the headache is greatly relieved; and the skin is cooler and softer. The pulse may not yet be altered, or it may be a few beats slower than before, but there is almost always already an improved appearance in the tongue, which shews a beginning disposition to clean. These favourable changes gradually increase. If the sleep the next night be longer and more refreshing, which it generally is, on the following morning a decided improvement is visible in the countenance. The eye is clearer and more lively, and the expression of the countenance is more natural. The skin continues cooler and softer; the tongue is still cleaner, and the pulse, perhaps, slower by a beat or two; and from this period, if no untoward event happen, the convalescence proceeds just as has been described in the return of health in the milder form of fever.
If, on the contrary, the case proceed unfavourably, a totally new train of symptoms at this period sets in.
1. In the first place, the pain of the head obviously, and sometimes strikingly, diminishes. Often it disappears altogether, or, if any uneasiness remain, it is rather a sense of dullness and heaviness than pain. In like manner the giddiness, if that were urgent, is no longer perceptible: but it is remarkable that the pain in the back and loins not unfrequently continues for some time after the headache has disappeared: but, ultimately, that also ceases. The period at which this important change takes place depends upon the severity of the attack, and is materially influenced by the activity or inertness of the treatment. In the subacute form, it usually takes place about the tenth day from the commencement of the disease.
2. Simultaneously with the disappearance of the head-ache, there is a remarkable diminution of the sensibility. The mind is duller and more heavy. The patient may still be roused to answer with tolerable coherence if spoken to; but when left to himself he is confused and stupid. The eyes now become injected: often suffused; and the heaviness and dullness of their expression is increased.
3. It is at this time that delirium, if it appear at all, most commonly comes on. The increasing insensibility, if not attended with decided delirium, is almost always accompanied with moaning or incoherent muttering, especially during the short and interrupted slumbers which form the substitute for sleep.
4. Striking as these changes are in the functions of the spinal cord and brain, those which take place in the number and character of the pulse are no less important. Even in cases the most decidedly subacute, it is seldom that it does not rise ten beats, so that if before it were 90, it will now be 100, and it is always weaker.