THE BEGINNINGS OF LIFE. 39 



was practically dead 1 but for the fact that the heart still 

 exhibited feeble contractions 2 , although the presence of 

 the ligature still prevented the egress of blood from its 

 cavities. In this condition the frog might be allowed 

 to remain for even three or four hours , and yet, when 

 the ligature was removed, the heart still continuing to 

 beat, the circulation soon became completely re-estab- 

 lished. The other vital functions reappeared much more 

 slowly. After about half-an-hour the first signs of 

 respiratory movements showed themselves at first at 

 irregular and distant intervals, and then, gradually, with 

 their accustomed rhythm. But it was not till after about 

 two hours more that the spinal cord, as a whole, re- 

 gained its excitability, and that reflex movements were 

 producible by irritation of the skin. Later still, the 

 power of voluntary movement was resumed, and the pre- 

 viously dead animal was seen to have recovered all its 

 vital powers 3 . 



1 The animal, as a whole, was certainly dead, although it retained 

 within itself the potentiality of living. Life might be renewed, if its 

 tissues and organs were again exposed to fitting conditions, but not 

 otherwise. 



2 We have seen, already, how long even in the human subject signs 

 of vitality remain in the right auricle of the heart. All this is much more 

 manifest in the Amphibia, and, from what has been stated above, we 

 can only conclude that the cardiac ganglia, in these creatures as well as in 

 others, are capable of retaining their vital properties longer than the 

 spinal centres. 



3 M. Gavarret calls attention to the Memoir of Legallois published 

 in 1812, ' Sur le Principe de la Vie,' in which he showed a rare insight 

 and prescience. Legallois said (CEuvres, t. i. p. 131) : ' Si Ton pouvait 

 supplier au cceur par une sorte d'injection et si en meTne temps on^avait, 



