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. 5. Now, too, signs of disease in the chest and abdomen are almost always to be distinguished. A case purely cerebral, from the commencement to the termination of the disease, is rarely to be met with. If there be not cough, there is almost always a short and hurried respiration, and more or fewer of the indications of abdominal affection hereafter to be stated. Even in cases the most purely cerebral the tongue always becomes more loaded and often dry; and it is strikingly characteristic of the state of the nervous system, that while the tongue becomes dry, the thirst diminishes. Thus far it is possible that the disease may proceed towards a fatal termination without proving mortal. It is not often that its course is turned back or stayed after it has made this progress; but still such an event is sometimes witnessed. When it does occur, the amendment, both in its origin and progress, is very similar to that of the favourable change which has already been described. More tranquil and longer-continued sleep is almost always the earliest sign that, in this severe struggle, life has obtained the victory. If, on awaking from such sleep, there be less delirium, were delirium present, or greater tranquillity, were the restlessness urgent; and if there be _any_ increase, although slight, in the sensibility, or any improvement in the expression of the countenance, hope may be entertained that that victory will be won; and hope may become assurance, if the tongue which had been loaded become clean at the edges, or the dry tongue become moist. Even under apparently the most desperate circumstances, if these three symptoms concur, a favourable prognosis may be pronounced with tolerable certainty. Two or three days _may_ elapse after their occurrence, before any remarkable change is observable in the pulse; but it is seldom that they continue twenty-four hours before the pulse falls at least ten beats. Now and then, on leaving a patient in the evening with a pulse at 120, we are surprised and delighted to find it in the morning as low as 100. When the pulse has thus fallen towards the natural standard, when the tongue has begun to clean, and when the skin has become cool and soft, however desperate his condition but a few days before, the patient may be said to be convalescent.