which in its results, is identical with that which previously affected the motor centres only.

Under the influence of an effectual dose, a child often presents the aspect of sleep. Suddenly compelled by the overspreading muscular lethargy to relinquish his amusements, he lays his head upon the carpet, the lids are seen to droop over the dull listless eyes, and disinclined-probably from a degree of torpidity of the hypoglossal centre-for speech, the child is content to lie tranquil. To a superficial observer he appears to be asleep, and if the effects of the conium be prolonged he may really become so. But such an event will rarely happen to an adult. His mind will continue during the whole action of the hemlock as calm and active as was Socrates' when he said to his friend, Crito, we owe Esculapius a cock; pay the debt, and do not forget it.' And he will tell us that he feels a strong desire to keep the eyes closed and remain quiet and undisturbed.

In poisonous doses the eyes will be completely fixed and the pupils dilated; articulation and deglutition impossible; expression and all other power of motion gone, and yet, while there is every appearance of the most profound coma, the perceptive faculties and reasoning powers may be as acute as ever. Such a condition I believe is not an uncommon one in other states than that produced by hemlock.

Like the cerebrum, the sensory part of the nervous system is altogether unaffected directly by the action of conium. Its anodyne power in certain diseases (see p. 54) may be fairly attributed to muscular relaxation in the diseased parts rather than to a direct influence upon the sensory nerves, conium being to the muscular apparatus involved what the knife, for example, is to irritable ulcer of the sphincter muscle of the bowel. Of its anodyne influence upon the facial branches of the fifth nerve, I have been unable hitherto to obtain other than very doubtful evidence; but in the painful dentition of children, I know of no anodyne so valuable as hemlock. Here indeed we fail to recognise painful compression of sensitive nerves by muscular contraction, but we have, as a consequence of a slight irritation of the dental branches of the fifth nerve, a general irritability of the

motor centres, often so excessive as to result in convulsions. Probably in such a condition, there is a perpetual reaction of the motory and sensory centres one upon the other, converting a peripheral irritation into a centric pain. I think, therefore, that we may trace the anodyne influence which hemlock undoubtedly exercises over the sensory branches of the fifth nerve, to the power that it possesses of calming the general irritability of the motor centres, rather than to a direct and exceptional action upon the sensitive nerve itself.

During the action of hemlock a sensation of muscular weariness almost amounting to aching is not uncommon, particularly if bodily exertion be continued the while. Other muscular sensations may occasionally be present. In a case of partial paraplegia in which I employed conium as a means of quieting the reflex jerkings of the limbs, the patient, in addition to the usual symptoms of its action, always experienced a deep-seated intermittent tingling sensation pervading the limbs to their extremities. It was different in character and more intense than the vibrations produced by the mildest current of the magneto-electric machine, with the sensations produced by which he was quite familiar. It came on with a gentle creeping action every few minutes, and lasted only a few seconds at a time. Invariably associated with the muscular weakness it passed off with it after continuing for about thirty minutes. What I have said of the influence of conium upon the cerebrum and centres of sensation, is equally applicable to the sympathetic nervous system. Conium has no influence upon the circulating organs, upon the secretions, or excretions, or directly upon nutrition. Its influence upon the sexual function (see p. 50) is traceable to a direct action upon the spinal cord.

The dilatation of the pupils arises from a depression of the centre of the third nerve, and not from a stimulant action of the sympathetic.

Excepting as a transient emotional effect in nervous individuals upon the sudden accession of the symptoms after a first dose of hemlock, the heart and blood vessels are absolutely unaffected by its operation. I have carefully

determined this in persons of all ages-in the weakly infant not three months old; in the strong and the debilitated; and in those who have intermittent action of the heart.

The sudden accession of the symptoms after a first dose of hemlock will in a nervous person sometimes excite the action of the heart for a few minutes, or induce a slight feeling of nausea, or a cold sweat, or even an action of the bowels; but these emotional effects are very rare, and when they occur are totally independent of the action of hemlock.

As to its effects upon nutrition, I have administered conium for months-in one case for more than six months (see p. 24) -and in such doses as have daily produced its peculiar physiological action, and the result has invariably been an improvement in the general nutrition and vigour of the body. This is true even when the drug is taken in poisonous doses; thus John Hunter's patient took one ounce of extract of hemlock in the course of the day for some time, and increased the dose to two and a half ounces. It produced indistinct vision and blindness, loss of voice, falling of the lower jaw, and a temporary palsy of the extremities, and once or twice a loss of sensation, and notwithstanding he was almost every night in a state as it were of complete intoxication from the hemlock, his health did not suffer, but on the contrary kept pace with the improvement in the ulcers' for which the medicine was prescribed. Ultimately the patient killed himself by taking in the course of the morning an ounce and a quarter of the extract.' It is doubtless by removing sources of central irritation that conium acts thus indirectly in improving the nutrition of the body.

Having now completed my observations on the physiological effects of hemlock in medicinal doses and short of producing toxical effects, I cannot conclude without advancing an inquiry respecting its primary action upon the nervous centres from whence the effects above-recorded issue. I take it for granted that conia represents the whole of the active principle of hemlock. But whether it exercises its powerful and subtle influence as conia or as some product of John Hunter's works, by James F. Palmer, vol. ii. p. 379.

its decomposition is doubtful. Unlike several other poisonous agents, conia does not pass through the system unchanged; and it is probable that it exercises its power at the instant of its decomposition. I have assured myself that conia as such does not pass out of the system. It cannot be detected in either the breath, the sweat, the fæces, or the urine.

I have carefully examined the urine voided immediately before and from 1 to 24 hours after the administration of large doses of conium many times, and find that this excretion is in no way altered by the powerful action of the medicine in the system.

Pupils

The following is a typical case:-John R., aged 57, a powerful smith, affected with muscular tremor of the left hand. He took a meal of tea, bread and butter, with a little fish, at 5.30 P.M., and emptied the bladder at 7.30 P.M. At 7.45 he emptied the bladder a second time, and took fl. 3j. of the succus conii. Half an hour after, he was suddenly seized with giddiness and weakness of the legs, and was unable to stand or walk for a quarter of an hour. During the next quarter of an hour he continued very tottering, but could walk slowly with assistance. Pulse 72, unchanged. unchanged. For the next hour he remained quiet, feeling great heaviness of the eyelids, and a tendency to sleep. At the end of this time the giddiness and weakness of the legs had entirely passed off. The pulse throughout was 72, and of good volume and power. The pupils which at the commencement measured the 4th of an inch in diameter were now dilated to nearly 4th. Two and a quarter hours after taking the medicine, and having had nothing whatever in the interim, the patient emptied the bladder a third time, voiding fl. Živss. of urine. The urine passed on taking the dose (urine A), and that voided 24 hours afterwards (urine B) were examined. Both specimens had precisely the same physical charactersa full sherry colour, clear, naturally acid, and a specific gravity of 1023.2.

Urine B was examined for conia, but not a trace of it could be detected.

In some cases, the solid constituents were more abundant in the urine passed before the action of medicine; in others, more abundant in that passed after the operation of the drug; the variations in all cases having reference to the time of ingestion of the last meal, and being altogether independent of the action of the conium.

cesses.

In examining the urine for conia I have adopted two proFirst, after precipitating the chlorine and urea by solutions of nitrate of silver and proto-nitrate of mercury, the clear filtrate was placed in a flat dish and allowed to evaporate spontaneously in a warm room. The crystalline matter and light brown syrupy residue were then supersaturated with caustic potash, and washed with æther. The æther was separated and allowed to distil from a water bath. When the caustic potash was added, a strong odour of conia, and one that bore the test of comparison side by side with an aqueous solution of conia, or extract of conia mixed with potash, was evolved; and I concluded for a time that I had found conia in the urine. This, however, was a mistake; for on repeating the process on two mixtures-the one composed of equal quantities of the urines of three patients passed immediately before administering conium to them, and the other composed of the same quantities of their urine secreted during the operation of an aggregate dose of fl. 3 xvij. of succus conii-I found that both evolved a strong and decided conia odour, and side by side it was impossible to distinguish the least difference between them. From both mixtures the æther extracted a minute film of oily matter free from any trace of conia. I mention this fallacy in order to show that in examining the animal fluids or tissues for conia, we must bear in mind that the addition of caustic potash to them will often develope an odour indistinguishable from conia, and that nothing short of the isolation of the principle itself should satisfy us (see page 81). It is for this reason that I cannot attach any value to Mr. Judd's observation, that the blood, thecal fluid, portions of the cerebrum, of the spinal cord, and of the muscles of cats