Here, however, it must be remarked that there is considerable variance between Harley and other observers; although perhaps a part of the difference is more apparent than real. Harley states that a full dose of the succus (five to six drachms) acts in the following manner, according to circumstances: if the taker keep up a brisk walking exercise, in half or three-fourths of an hour he feels a sense of weariness in the legs, with some giddiness and heaviness over the eyes, but if he persevere in his walk these symptoms soon pass off. If, on the contrary, he remain at rest after the dose, the eyes become first affected; accommodation is interfered with, and then there are drowsiness and dilatation of the pupil; after these come weakness of the legs; pallor, inability to stand steady, a general diminution of muscular power, especially in the hamstring muscles. From the consideration of these facts, and from the results (hereafter to be mentioned) which conium afforded him in the treatment of chorea, etc., Harley believes that the central motor tract is affected by conium, and that its action (in full and repeated doses) is primarily tranquillizing, and subsequently tonic, to the muscular movements. He particularly states that the vertiginous and quasi-paralytic effects are much more pronounced in those who are quiescent than in subjects who are active; so that a delicate child, if lively and running about, will take with impunity a dose that would muddle a sedentary adult.

As regards the production of dizziness, impaired accommodation, dilated pupil, and other narcotic brain symptoms, although there are some observers who deny them, a great preponderance of evidence is confirmatory; 1 but they appear on the whole to be trifling in comparison with the effects on the motor system.

Upon the sensory nerves coniine appears to exert a direct, but moderate, paralyzing influence, which is local in action. Applied to a nerve laid bare, it causes no pain, but simply interrupts the conduction of sensory impressions. There is no reason to think that it at all affects sensation by any action on the nervous centres. It is said, however, that the first momentary effect of applying coniine to a wound, or to the mucous membrane of the mouth, is a burning feeling; but this sensation is immediately succeeded by a loss of sensibility, and there is no ground for viewing coniine objectively as an irritant.

The question whether conium affects the heart, and, if so, how, remains undecided. The general result of experiments on animals certainly discountenances belief in any direct action on the heart; as to human beings, the evidence is more conflicting. J. Harley declares that there is usually little or no effect; but the pulse may, if anything, become firmer and fuller.

1 See especially Schroff's account of the experiments made under his control by Dillnberger and Dwoizall.

The known general physiological character of the drug entitles us to treat its action on the heart as but of slight consequence.

Conium was formerly credited with diuretic and diaphoretic action; but the evidence is very conflicting. Some weight may perhaps be given to the affirmation by several American physicians of its diaphoretic powers; but the assertion of Fountain that this result is equally produced by coniine and the extract of hemlock is obviously open to great suspicion.

Of the fatally poisonous effects either of hemlock or of conia upon man, we possess very little information; it is desirable, therefore, to take particular notice of any well-observed case. Dr. Hughes Bennett recorded the case of a man who ate hemlock in mistake for something else in a salad; the first symptom observed was weakness of the legs, producing faltering gait; as the weakness increased the man staggered as if drunk, and, at the same time, the arms began to be paralyzed. Perfect loss of all voluntary movement, including swallowing, followed; and, lastly, palsy of respiration put an end to his life. Consciousness and intelligence were unimpaired up to death, but sight was destroyed. It is worthy of notice that in this case there seems to have been no primary brain affection.

The account of the physiological action of conium and coniine would be very incomplete if it did not include the observations of Drs. Fraser and Crum-Brown. They made the very important discovery that, at any rate in Britain, there are two varieties of coniine sold, of which one (Morson's) really contains not only coniine, but a compound of it - me-thyl-coniine, the properties of which are very different from those of pure coniine. Methyl-coniine was carefully investigated by them, and was found to have the power of influencing not only the motor-nerves, but the spinal cord itself; with large doses the former action is completed before the latter, but with small doses the action on the cord is completed before that on the nerves. It is evident that in proportion to the varying degrees in which the so-called coniine may contain methyl-coniine, the effects vary. Hence the discrepancies of different authors.

Therapeutic Action. - The therapeutics of conium are quite new: in fact, they have been altogether in the stage of discovery and conjecture up to the present time. For it must be remembered that such preparations as the extract - which was chiefly in use till a very few years ago - have been proved by various experimenters to be inert, even in doses greatly larger than it was the custom to employ, and the effects obtained with them must, therefore, have been imaginary. Indeed, the only trustworthy fact among the older observations on conium was the local sedative action.

As a Local Remedy for pain and irritation conium is occasionally very useful: the pain of cancer seems to be, for some reason, particularly amenable to its influence. The best application to a scirrhous breast, for example, which is in the stage of painful tension, immediately before ulceration, or even in the ulcerative stage itself, is a mixture of the succus conii and glycerine in equal parts, or a very weak solution of coniine, or a poultice of the fresh leaves. For cancer of the stomach the succus may be given in doses of two to five drachms or more; and to allay the pain of cancer of the rectum, one ounce of succus may be injected with one ounce of starch-decoction. In the painful "scrofulous" photophobia Dr. Mauthner has employed coniine most successfully; he used a mixture of 1/2 grain coniine with a drachm of almond oil, a little of which was applied two or three times daily to the conjunctivae. The irritability and soreness of the air-passages in bronchitis, and in the tickling cough of phthisis, can be admirably calmed by the inhalation of coniine-vapor. Harley's formula is the best: coniine, 1 gr., alcohol 3 iss.; dissolve the coniine in 3 ss. of the spirit, and add the remainder with 3 ij. of water: m, xx. contain 1/12 gr. of coniine, and form a proper dose to be placed on a sponge in a suitable apparatus.