CHEMICAL CONSTITUTION AND PHYSIOLOGICAL ACTION. 695 



ments. With the exception of these rare gasps, and of a continuance of the 

 cardiac contractions, at the rate of 100 beats in the minute, the animal appeared 

 to be quite dead at twenty-seven minutes after the injection; for even the 

 sensibility of the skin, conjunctiva, and cornea was at this time suspended. 

 The respiratory gasps, however, continued at the rate of five or six in the 

 minute, until thirty-two minutes after the administration of the poison, when 

 death occurred. 



In autopsy, it was found, five minutes after death, that the heart was beating 

 at the rate of 96 per minute. The conductivity of the motor nerves and the con- 

 tractility of the muscles were retained for several minutes afterwards. 



The dog, which was the subject of this experiment, had received, some weeks 

 previously, ten grains of sulphate of atropia; and it will be seen from the follow- 

 ing account of the experiment, that this dose produced in it some of the more 

 prominent effects of atropia-poisoning. 



Experiment XXII.— Ten grains of sulphate of atropia was dissolved in fifty 

 minims of distilled water, and injected under the skin of the dog that was 

 used, some weeks afterwards, in Experiment I. Omitting many details of the 

 earlier symptoms that were observed, it is sufficient for our present purpose to 

 mention, that in five minutes, there was evident impairment of vision ; that in 

 seven minutes, some efforts were made to vomit ; that in twelve minutes, urine 

 was voided; that in thirteen minutes, partial paralysis was decidedly present; 

 and that in thirty-eight minutes, frequent spasmodic starts and marked exag- 

 geration of the reflex excitability coexisted with considerable lose of voluntary 

 motor power. After this time, certain effects were observed that contrast in a 

 remarkable manner with those observed in the previous experiment. Gradually 

 the paralysis became more marked until the dog was unable to support itself on 

 its limbs ; and the spasmodic action acquired a greater prominence, so that, in a 

 short time, it produced violent tetanic convulsions of an opisthotonic character. 

 The first of these convulsions occurred at fifty-two minutes, and it was succeeded 

 by a series, following each other at intervals of eight or nine minutes, until four 

 hours and ten minutes after the administration, when the observations were 

 interrupted. At nine hours, the dog was still affected with considerable para- 

 lysis, but no tetanic convulsions now occurred, though spasmodic starts and 

 exaggeration of the reflex excitability had not yet disappeared. On the following 

 morning, the dog was running about, and it ultimately recovered perfectly. 



These two experiments appear to show that the chemical addition of iodide 

 of methyl to atropia increases the lethal activity, and removes the convulsant 

 action of this alkaloid. These changes have been carefully examined in many 

 experiments on rabbits and frogs. In rabbits, we have ascertained that a dose 

 of two and a-half grains produces marked paralytic symptoms, which do not 

 terminate in death ; while three grains is a sufficient dose to kill a large animal. 



