THE BEGINNINGS OF LIFE. 27 



to state that this contractility of the muscle can be ex- 

 cited, for a time, after the death of the animal of which 

 it formed part : the length of time during which the 

 property persists being, generally, longer in proportion 

 as the animal is lower in the scale of organization. 

 During winter the muscles of certain fish and reptiles 

 have been known to contract for a 'week after death, 

 though in mammals and birds this property of the vo- 

 luntary muscles disappears after a few hours. From the 

 researches of Nysten upon the bodies of decapitated 

 criminals, it appears that in man, as in the lower ani- 

 mals, a certain order is observed amongst the different 

 muscles of the body in the loss of this vital property. 

 Contractions,, from electrical stimuli, ceased in the left 

 ventricle of the heart after forty-five minutes; in the 

 muscles of the extremities after seven hours ; and, last 

 of all, in the right auricle of the heart, which, on this 

 account, had been previously spoken of by Galen as 

 c ultimum moriens/ In one instance, Nysten found 

 that this portion of the human heart could be made to 

 contract i6| hours after the death of the individual. 

 Contractility of the muscle cannot, therefore, be due 

 to any peculiar c vital principle ' which leaves the body 

 when the organism dies. 



Although the muscle is usually excited to contract by 

 a stimulus sent through a nerve, we have now learned 

 principally through the phenomena observable in ani- 

 mals poisoned by woorara that the contractility of the 

 muscle may be called into play through the direct 



