156 Prof. T. R. Fraser and Dr. J. Tillie. On the [Mar. 23, 



movements like those of vomiting; fibrillary twitching of muscles, 

 especially at the seat of injection ; impairment of motor power and 

 of co-ordination ; disappearance of the cardiac impact ; cessation of 

 respiration ; and gradual enfeeblement and loss of reflex and voluntary 

 movement. 



On opening the thorax, the heart is found motionless, the ventricle 

 in extreme systole, the auricles distended with blood, and the whole 

 heart inexcitable to mechanical or electric stimulation. When, how- 

 ever, the precise minimum lethal dose has been administered, the 

 heart is found to have been arrested in extreme diastole, and it 

 responds to stimulation. Immediately after death, stimulation of a 

 motor nerve causes muscular contraction ; but, soon thereafter, the 

 muscles cease to respond to stimulation of the nerves or to direct 

 irritation, and become acid in reaction and rigid. 



In the rabbit, after the subcutaneous administration of a minimum 

 lethal dose, the most important phenomena are gradual impairment 

 and failure of the heart's action, of respiration, and of motor power. 

 Just before death the cardiac pulsations become slow and extremely 

 feeble, but the rate is estimated with difficulty by palpation of the 

 thorax on account of frequent muscular twitchings. The respiration 

 is rendered slow, irregular, and shallow. Inspiratory difficulty 

 occasionally becomes so great that death from asphyxia seems im- 

 pending even when the cardiac pulsations and general motor power 

 appear good. Motor power is usually so much reduced before death, 

 that the animal lies prostrate ; and only a few feeble movements of 

 the body indicate the arrest of the heart. When the dose is large, 

 or when the poison acts with unusual rapidity, the heart is paralysed 

 before the general motor depression has set in, and sharp convulsive 

 movements follow the arrest of the circulation. It is sometimes 

 difficult to say whether the cardiac or the respiratory movements 

 cease first. Usually, respiration is distinctly continued for a brief 

 period after the heart can no longer be felt to pulsate, and on post- 

 mortem examination, the bright red colour of the left auricle and the 

 pulmonary veins contrasts strongly with the dark colour of the right 

 auricle. Sometimes cardiac movements occur after the respiration 

 has finally ceased, but immediate post-mortem examination reveals 

 that the pulsations are mere irregular movements, altogether in- 

 sufficient to sustain life or to indicate that the arrest of respiration 

 was the cause of death. The left ventricle is usually found con- 

 tracted and nearly empty, and the right ventricle and the auricles 

 filled with blood. Most frequently the heart is motionless, and does 

 not respond to mechanical or electrical stimulation, but it sometimes 

 shows spontaneous quivering movements, and, for a very brief 

 period, may respond to stimulation. The lungs are of a light pink 

 colour. After death, the motor nerves soon lose all influence over 



