that accompanies the tobacco-habit also sustains this hypothesis; and this may be produced in animals by introducing a very minute dose of decoction of tobacco into the system by way of the mouth, while subcutaneous injection is not equally rapid in producing this special result, nor, indeed, in producing death. Nor have I any doubt, from the few experiments I have tried, and the many I have witnessed, that, in opium-smoking, the peculiar symptoms are occasioned by a similar action of the vapor of the drug (on the medullary tract by way of the pneumogastric nerves). The olfactory nerves are, of course, more or less affected, and transmit the specific influence of either drug directly to the interior lobes of the brain; but experiment and observation alike tend to the conclusion that, though dizziness is somewhat accelerated by this action, it is trifling even in its cerebral effect, and that the great thoroughfare of activity is by way of the pneumogastric. The disturbances in locomotion arising from tobacco are thus secondary effects propagated, not by way of general nervous disturbance, but by direct appeal to the great coordinating centre, the cerebellum, through the near-lying and directly-connected vital tract. The vertiginous symptoms that accompany disturbances of the latter class must not be confounded with those that originate by way of the olfactory nerves, as the whirling sensation is far more marked and distinct in cerebellar disturbances, while the tendency to unconsciousness is somewhat less so.
I am, in these remarks, let it be understood, simply giving the results of my own observations on my own person during the last thirteen years; and my conclusion, from the masses of data thus accumulated, is, that the great sensory and motor tract of gray neurine, known as the cortex, is not at all involved in the primary stages of the narcotism induced by smoking, though the reverse is often clearly true in the instance of opium, with its surer and swifter cerebral effect. Others may be very differently affected by habitual smoking. I simply contribute my leaf to the record; and, although I am not satisfied that the tobacco-habit ever produces neurosis, I am satisfied that it is often the exciting cause of nervous disorder in cases where the neurotic tendency exists, and that in these cases it is productive sometimes of morbid moral phenomena, in a degree only less marked than the epileptic aura, and penetrating to the very roots of volition and ethical emotion. My opportunities for observation in hospitals and asylums have not been extensive enough to permit me to pronounce definitely on the point I am about to suggest; but it is my impression that the larvated type of epilepsy occurs more frequently than any other among persons addicted to tobacco, and that the habit is very generally influential in the larvation of nervous maladies. Statistics only can settle this issue, which must be left to the consideration of medical psychologists.
In order that the lay reader may clearly apprehend the various
