Movements of the Heart of the Copper-head Snake. 33 



according to Colin,* is 24 beats per minute, or accorclinc)- to 

 Burdacli,f 3-i per minute, but from the above table, it is seen 

 that this rate is exceeded when the heart of the chloroformed 

 snake is observed, either attached and within its pericardium, 

 or detached. 



It may be mentioned that in the chloroformed snakes, the 

 right auricle was distended with blood, while the left was 

 flabby and empty. The explanation usually given, that the 

 heart is distended after death by chloroform, owing to its 

 want of power to contract, is negatived by these observations ; 

 for surely it will be conceded, that a heart which can execute 

 movements and pulsate for hours, is not lacking in a 

 considerable amount of stored up energy. But a probable 

 explanation of the fact that the right side of the heart 

 retains its blood, while the left side is deprived of it, lies in this, 

 that the lungs (in this case lung) cease to perform their 

 proper functions, that respiration is arrested, and so blood 

 ceases to be received by the lungs through the pulmonary 

 artery, or from them through the pulmonary veins, although 

 the muscular, still living and active heart, continues to 

 pulsate. And this suggests the question — Can a body be said 

 to be dead entirely, while the heart within it is living and 

 active ? Death is the cessation of vital activity, but we 

 cannot say that the progressing and pulsating heart does not 

 exhibit activity of a vital kind, so that somatic death need 

 not include cardiac death. Poets, novelists, and even 

 scientists have spoken of the pulse of the heart being stilled 

 by the gentle hand of death, but there may be death to all 

 outward appearance, and still the heart beats — life at least 

 cannot be said to be extinct. Professor MacAlister, of 

 Cambridge, says| that stoppage of the heart and cessation of 

 life are simultaneous in man and the higher warm-blooded 

 animals, but I have observed the excised heart of a kitten to 

 travel i inch forward and 1|- inch to right, and pulsate as a 

 whole for 5 hours 12 minutes. It seems to me that death 

 can only be accurately defined as stoppage of the heart's action, 

 or rather, if this action be regarded as due to nerve 

 substance, then the death of the nerves, or that part which 

 co-ordinates, would be the final test. At present, however, 

 in the Vertebrata at least, we may speak of partial or 

 somatic death, and complete or cardiac death. 



* See Landois and Stirliug's Text-book of Physiology, 

 t Pbysiologie, Vol. iv, p. 25. 



I Man, Physiologically Considered. Eeligious Tract Society. 



D 



