Dr. Ballard also, (in Ballard and Garrod's Materia Medica,) states that Tonics acts first upon the nerves, and through them on the muscular system. He opposes them to Sedatives, and ranks them with stimulants; quoting Strychnia as an example of a stimulant which gives tone to the muscular system. But, in the first place, this alkaloid is quite exceptional among stimulants; and further, the comparison with Tonics seems unnatural, inasmuch as the action of Strychnia is more or less immediate, not slow and permanent, and it evidently influences the spinal system of nerves in the first place.
The results of large doses of Quina, in producing determination of blood to the head, ringing in the ears, and vomiting, seem to me to mark its action as an irritant poison, and not to be characteristic of Tonic medicines. (Vide p. 91.)
The action of Tonics has been more correctly defined by another able authority. "Tonics," says Dr. A. Billing, "are substances which neither immediately nor sensibly call forth actions, like stimulants, nor repress them, like sedatives, but give power to the nervous system to generate or secrete the nervous influence by which the whole frame is strengthened."
This definition I would accept in a modified sense, considering that no permanent alteration in the nervous system can be produced without a primary impression on the blood. Dr. Billing further considers, that the supposed stimulant action of Tonics in some cases should either be attributed to the operation of the disease, or of some other medicine administered along with them; and that though in large doses they may sometimes produce a quick pulse with headache, and in other instances depression with nausea, yet that these effects should be ascribed merely to their irritating action on the stomach.
On the whole, it seems to me that those authors who, in defining the action of Tonics, have commenced by saying that they act on the nervous system, have started with a mistaken notion; and I am more of the opinion of Dr. A. T. Thomson, who classes them as medicines which act on the muscular and sanguiferous systems.
I consider, then, that Quina is not in the first instance a Neurotic medicine; and for the following reasons. The action of other nerve-medicines is distinguished by the following signs. It is quick, and very rapidly follows the administration of a substance. It is transient, and does not endure. It requires no particular state, but takes place in health: thus Alcohol stimulates and intoxicates both healthy and sickly, and Digitalis would subdue a Hercules. Most Neurotics are capable of acting without entry into the blood at large; mere contact with the nerves, as when they are applied externally, being sufficient for their action on those nerves. Again, Neurotics are chiefly used in cases in which the nervous system is unusually excited or depressed, and are of no permanent efficacy in diseases depending on blood-disorder. The action of Hæmatics is of an opposite kind.
Now is the primary action of Tonics distinguished by the above signs? Are they quick and sudden in action? Is their effect transitory? Is it evidenced in health as well as in disease? Do they act on the superficial nerves, when applied to them? In each case the answer must be a negative. In all of these particulars the operation of vegetable bitters differs from that of Neurotics, and coincides with that of Hæmatic medicines.
It appears that their action on the nervous and muscular systems is secondary. They could hardly in either case effect any permanent improvement without first acting on the blood, if we may argue from known analogies. For Neurotics and Astringents, which operate directly on these two systems, are alike transitory in the results of their action.
Another demonstration is required, before the presumption thus established can approach to a certainty.
We require proof to show that the disorders in which Tonics are used are blood-diseases. This does not seem to be difficult.