372 THE POPULAR SCIENCE MONTHLY. 



a solution of curari is injected under the skin than when the dry poison 

 is introduced by the point of an arrow. Vigorous animals with rapid 

 circulation of blood are more easily poisoned than those which are 

 weakly ; and with an equal dose of poison and with animals of equal 

 size, those whose temperature is constant die more quickly than those 

 whose temperature is variable (reptiles, batrachians, fishes), and, among 

 the former, birds succumb more quickly than mammals. 



The animal at first does not feel the wound, for curari possesses no 

 caustic property. In the case of very small animals death is almost 

 instantaneous. In birds and mammals of a large size, and in all ani- 

 mals of variable temperature, death usually occurs in from five to twelve 

 minutes, if there is an excess of the poison. The animal lies down as 

 though it would sleep, keeping the eyes open, with a placid expression. 

 Soon it is seized with a progressive paralysis of the motor nerves, pro- 

 ceeding from the extremities to the centre. The muscles of respiratory 

 movement are the last to succumb, and the animal dies from asphyxia. 



To all appearance, nothing could be calmer than this progressive 

 state of stupor ; there is no agitation, no expression of sufi"ering. The 

 mouth remains shut, without foam or saliva. Life seems to be extin- 

 guished slowly, like some liquid that gradually flows away. In view 

 of these treacherous symptoms, a member of the Society for the Pre- 

 vention of Cruelty to Animals might be tempted to urge the use of 

 curari in lieu of the brutal modes at present in vogue for slaughtering 

 old, worn-out horses. 



To Claude Bernard science is indebted for the exact determination 

 of the specific action of curari. Vital activity presents a threefold 

 series of distinct and coordinated organic elements, which play the 

 part of excitants of one another. The starting-point of physiological 

 action is the sensitive nerve-element. Its vibration is transmitted 

 along its axis, and on reaching the nerve-cell — a regular relay — the 

 sensory vibration is transformed into a motor vibration. This lat- 

 ter, in turn, is propagated through the motor nerve-element, and on 

 reaching its peripheric extremity causes the fibre of the muscle to 

 vibrate, and this, reacting in virtue of its essential property, produces 

 contraction, and consequently motion. 



Now, each of the three elements, sensory, motor, and muscular, lives 

 and dies after a fashion of its own, and there are poisons proper to 

 each. But, inasmuch as vital manifestations require the cooperation 

 of these three activities, if one be suppressed, the other two continue 

 to live indeed, but they no longer mean anything, just as a phrase loses 

 its meaning if one of its members be dropped out. Claude Bernard's 

 experiments have proved that the motor nerve-element alone is affected 

 by curari, and that the other two organic elements of the animal retain 

 their physiological properties. Tlie mind is not destroyed, the muscu- 

 lar fibre still has the power of contraction, and indeed does contract 

 under the influence of electric discharges. Motor power alone is de- 



