Under this division of General Stimulants are included those which act quickly and energetically, but only for a comparatively short period. In the degree in which they possess the stimulant property they differ much among themselves; but, as a general rule, they greatly exceed, in this respect, the permanent stimulants, embracing the astringents and tonics, which have just been under consideration. One of the laws of all stimulation, whatever may be its degree, is that it is followed by a depression proportionate, at least approximately, to the previous exaltation of the function or functions excited. Hence, the remedies belonging to the present section, as they exceed the astringents and tonics in rapidity and extent of stimulant action, leave behind them a more speedy and greater depression.

General Therapeutic Remarks on Diffusible Stimulation.

The condition to which this therapeutic process is applicable, is obviously that of general depression of the actions or powers of the system. To a considerable extent, the observations made upon tonic stimulation in reference to the possible injury from its abuse, and to the conditions of depression or debility admitting and calling for its employment, are applicable also to this variety, and need not be repeated. Only a few remarks, more particularly bearing on the subject at present under consideration, are required.

As a general rule, the diffusible stimulants may be resorted to in cases of considerable, and especially of rather sudden or acute prostration, which tonics and nutritious food are either too slow in action, or too feeble in stimulant power to counteract. But some cautions are necessary.

Sometimes there is great prostration of the vital actions, depending on the concentration of blood and nervous power in some large organ, or extensive structure in the interior of the body, in a state of high inflammation. This may without caution be mistaken for real debility, and fatally treated under that impression. It occurs usually at or near the commencement of the inflammatory attack, and will in general be readily diagnosticated by the evidences of the existing inflammation, if the practitioner be on his guard. In these cases, bleeding is the great remedy, if it can be employed; the system reacting as the interior organs are unloaded, and the pulse rising under the lancet. But sometimes the least amount of blood lost so far impairs the powers of the heart as still further to depress the pulse. Under such circumstances, stimulation may become necessary in order to excite the heart, and rouse up the circulation generally, so that loss of blood may be borne, until the relief of the internal congestion shall remove the depressing force. But it is obvious that the stimulation must be such as will not be likely to continue into the period of reaction, as it would much aggravate the danger of inflammation. Therefore, reliance should mainly be placed on external stimulation, which can be withdrawn at any moment when de-sirable; and, if this should prove insufficient, the stimulants of briefest action should be preferred, as heat, the ammoniacal preparations, and those of ether.

Another analogous condition, in which precisely the same cautions should be observed, is that collapse of system which generally attends violent concussion of the brain, and not unfrequently occurs after any severe shock upon the system, as from accidental injury, or a Surgical operation. The nervous centres are here prostrated, and all the vital functions fail in consequence. Sometimes reaction never takes place; but when it does, inflammation and fever almost always ensue, and might be greatly aggravated by the previous injudicious use of stimulants. But these are sometimes essential to assure reaction. The external, and those of brief action are here also indicated; and those especially should be avoided which would peculiarly stimulate the organ likely to become the seat of inflammation, as the brain in concussion.

Again, collapse calling loudly for diffusible stimulation sometimes occurs in the cold stage of febrile diseases, particularly those of a typhous and malignant character, and the exanthematous. Here also reaction will take place if the patient survive; and, although equal caution in regard to prolonged stimulation is not necessary as in the former instances, the reaction itself being often tainted with debility, yet injury may be done by a too zealous employment of the measure, and the stimulants of long continued action, and greatest influence on the brain. should be resorted to only when it becomes obvious that external and brief internal stimulation will not answer.

But when debility occurs in the course of acute disease, as in the various febrile affections, diffusible stimulation may be employed without scruple, and usually in a degree exactly corresponding with the apparent call for it. Here there is no danger of subsequent reaction. The prominent indication is to support the system until the depressing agency shall have ceased, and either the system have recovered its energies, or the disease run its course.

Even the coexistence of inflammation does not, under such circumstances, altogether contraindicate the use of stimulants, though it should dispose to greater watchfulness not to exceed the necessary point. Various inflammations occur in the course of fevers of the low or typhoid character, in which the blood and nervous force are both greatly impaired, and often will not sustain life unless fay the aid of the diffusible stimulants. Local measures, even moderate cupping or leeching, fomentations, blisters, etc., and the careful use of the mercurials, may be employed for the inflammation, while stimulants may be freely used to support the functions, and nutritive matter to supply a better blood. This remark, too, is applicable even when the inflammation may have been the original affection, provided the symptoms of typhous debility, and a depraved or poisoned blood supervene. Examples of this kind we have in typhous pneumonia, typhous dysentery, malignant sore-throat, and the prostrate or malignant forms of scarlet fever, smallpox, and erysipelas; and there is scarcely one of the exanthematous fevers, or of the local inflammations to which the remark will not apply.

Another condition of debility, often demanding the free use of the diffusible stimulants, is that which attends acute febrile affection or inflammation occurring in persons previously worn out by enfeebling disease, bad living, or habits of intemperance. In the last case, it is generally necessary, even when the lancet may be employed for the cure of the inflammation, to administer stimulants to support the heart and nervous centres, which would refuse to act without them. This is an important therapeutic principle in the treatment of habitual drunkards, and even of those who have been long in the habit of using ardent spirits in great excess, though never obviously intoxicated.

Again, when the system is exhausted by profuse evacuations, as in the hemorrhages, cholera, diarrhoea, etc., by long-continued disease of almost any kind, or by copious suppuration, the result of antecedent inflammation, or is prostrated under the influence of gangrene from the same or some other cause, diffusible stimulants are often necessary to support life until the system recovers its powers, or the processes referred to shall have terminated, as they usually have a tendency to do, in health. Often, in these cases, tonics and a nutritious diet, or even the latter alone, may be sufficient; but frequently also the diffusible stimulants are essential.

Whenever, moreover, the blood becomes so impaired by an absorbed or otherwise introduced poison, as to be incompetent alone to the support of the vital functions, diffusible stimulants must be freely used, in order to sustain life as long as possible, in the hope that the poison may be thrown off, or that the blood and solid tissues may pass through the series of morbid changes set on foot by the poison, and return to the sound condition. Thus, purulent infection, the state of system resulting from poisoned wounds, as in dissection, and the poisonous condition produced by the bites of serpents and other venomous animals, will sometimes recover under potent stimulation, when the patient might perish without it.

Finally, there are diseases in which the nervous centres appear to be prostrated, without any observable vitiation of the blood, and without at first any considerable failure in the actions of the heart; in which, however, powerful stimulation is sometimes essential. Not to mention delirium tremens, in which this condition of the nervous centres results from the withdrawal of a wonted stimulus, and which often imperiously demands stimulation to save life, there are tetanus, and various other violent spasmodic and nervous affections, among which mania may be sometimes included, in which the same remedial measure is often of great importance.