CHEMICAL CONSTITUTION AND PHYSIOLOGICAL ACTION. 697 



These experiments are sufficient to illustrate the physiological effects that are 

 produced in rabbits by the subcutaneous administration of iodide of methyl- 

 atropium. They likewise show — and the result is confirmed by other experi- 

 ments briefly described in the table at the end of this paper — that iodide of 

 methyl-atropium is a much more active poison for rabbits than any salt of 

 atropia. We have already mentioned that the minimum fatal dose, by sub- 

 cutaneous administration, of even so soluble a salt as the sulphate of atropia, is 

 greater than fifteen grains ; whereas it is proved by Experiment VIII. that three 

 grains of iodide of methyl-atropium, administered subcutaneously, is a fatal dose 

 for a rabbit. 



We have not succeeded in obtaining any data by which to compare the 

 relative activity of these substances when given to rabbits by the stomach. We 

 have given in this manner as large a dose of both as thirty grains, but have 

 observed no obvious symptom with either substance, except dilatation of the 

 pupils. 



Though iodide of methyl-atropium is tolerably soluble in water, it is less so 

 than sulphate of atropia. In Part I. of this investigation we have mentioned as 

 a condition which it is advisable to fulfil, " that the substance is equally suitable 

 for absorption into the system before and after the change."* In conformity 

 with this condition, we have examined, with considerable care and detail, the 

 poisonous activity and physiological action of the sulphate of methyl-atropium, 

 a much more soluble salt than the iodide, and, therefore, a more suitable 

 substance for comparison with sulphate of atropia. 



Sulphate of methyl-atropium ((C 17 H 23 N0 3 CH 3 ) 2 S0 4 ). — This salt was prepared 

 from the iodide by the method formerly described for the preparation of the 

 sulphates of methyl-strychnium, methyl -brucium, &c. It is a white, crystalline 

 substance, very deliquescent, and very soluble in cold water. 



Apparently on account of its greater solubility, it is a rather more active salt 

 than the iodide; and both in rabbits and frogs its lethal activity was, accordingly, 

 found to be much greater than that of sulphate of atropia. 



We administered it to rabbits by injecting it under the skin, and also by 

 introducing it into the stomach. The symptoms produced by the former method 

 of administration are in character exactly the same as those produced by the 

 iodide, as will be seen from the following detailed account of several of our 

 experiments. 



Experiment XXXII. — We dissolved two grains of sulphate of methyl-atro- 

 pium in twenty-five minims of distilled water, and injected the solution under 

 the skin at the right flank of a rabbit, weighing three pounds and seven ounces 

 and a-half. In seven minutes, the animal moved about in an uneasy manner, 



* Transactions of the Roy. Soc. of Edinburgh, vol. xxv. part 1, 1867-68, p. 153. 

 VOL. XXV. PART II. 8 T 



