720 DRS CRUM BROWN AND FRASER ON THE CONNECTION BETWEEN 



of hydriodate of methyl-conia and iodide of dimethyl-conium — the former pro- 

 duced from the normal conia, and the latter from the methyl-conia. If the conia 

 be free from water, this action is very rapid, and as heat is developed it is 

 necessary that the vessel should be kept cool ; if the conia contain water, the 

 chemical change is very slowly effected. Caustic potash is added to the mixture, 

 and it decomposes the hydriodate of methyl-conia, setting the base free as an oil, 

 while it leaves the iodide of dimethyl-conium unacted upon. The methyl-conia 

 was converted, after separation, into a hydrochlorate, which is extremely deli- 

 quescent, and has a brownish, semicrystalline appearance. 



We found that this substance possesses a poisonous (lethal) activity, consider- 

 ably greater than that of Mr Morson's conia, but nearly equal to that of Dr 

 Christison's conia ; for two-tenths of a grain, exhibited by subcutaneous injection, 

 speedily caused death in a rabbit, and a dose, equivalent to the ^gVffth of the 

 weight of the animal, is about the minimum fatal dose for a frog. The general 

 character of the symptoms is likewise similar to that of Dr Christison's conia, 

 and, therefore, to that also of Mr Morson's ; but the causation of these symptoms 

 rather resembles that of the latter than of the former conia. Paralysis is the 

 main symptom ; and a careful examination, by experiments on frogs, of the 

 mechanism by which this symptom is produced, showed that it is a result of 

 actions on the motor nerves and spinal cord, and that with large doses the former 

 action is completed before the latter, while with small doses the latter action is 

 completed before the former. 



We shall, in the first place, describe the symptoms that appeared in a rabbit, 

 after the administration of a fatal dose. 



^Experiment LXXXI. — Two-tenths of a grain of hydrochlorate of methyl- 

 conia was dissolved in twenty-five minims of distilled water, and injected under 

 the skin at the right flank of a healthy rabbit, weighing two pounds and ten ounces 

 and-a-half. The rabbit moved about in a normal manner until four minutes after 

 the injection, when the movements became constrained, and it was observed that 

 this was owing to stiff extension of the four limbs. A slight touch of the animal 

 caused a series of rapid tremors, during which, as well as at other times, the body 

 was elevated on the stiffly extended limbs. This somewhat remarkable condition 

 continued without change until ten minutes, when the stiffness of the posterior 

 extremities disappeared ; but, in place of assuming a normally flexed position, 

 these extremities became flaccidly abducted ; and, when the animal moved about, 

 they trailed behind it in a somewhat powerless manner. In eighteen minutes, the 

 symptoms of exaggerated reflex activity, and the spasmodic extension of the anterior 

 extremities had disappeared ; and, now, there was so great a degree of general 

 paralysis present, that the rabbit was unable to move about, and it lay quietly on 

 the abdomen and chest. In nineteen minutes, the neck muscles could no longer 

 continuously support the head, which, soon after, rested on the table. In twenty 



