THE CONSEKVATION OF LIFE 215 



fiercely contested and declared to be false. But if we examine 

 the question itself on the basis of the facts we shall see that the 

 assumption of, as it were, an eternal life for numerous protozoa 

 is neither sophism nor playing with words, but a logical necessity, 

 unless indeed we wish to rob the conception of ' death ' of its 

 natural meaning. 



Let us first of all define the problem and agree upon the 

 meaning of the words. ' Death ' is distinguished from ' life ' by 

 two factors, one a physiological, the other a morphological. 

 Death is indicated by the cessation of the individual life-pheno- 

 mena and by the appearance of a corpse : only when these 

 conditions are fulfilled we are able to speak of death having 

 taken place. Let us apply this to the Amoeba. That there is 

 no appearance of a corpse or of anything that can be regarded 

 as equal to it we have already seen, for the mother divides into 

 two daughter-individuals without leaving a residue. Thus it 

 would seem that the question is already decided in our favour, but 

 the opponents of this doctrine of immortality cling in this specific 

 case to the physiological factors and contend that in reproduc- 

 tion by fission the mother ceases to exist as an individual, and 

 that the individual life-phenomena are thereby discontinued. To 

 a certain degree and with many modifications this conception 

 might be defended, but if we examine the question more 

 thoroughly it seems to me that we shall reach a different result. 



Like many higher animals and most protozoa, our Amoeba 

 possesses the important faculty of replacing lost parts of the 

 body by regeneration. If I cut from the body of the Amoeba 

 a particle of protoplasm it does not perish from this injury. On 

 the contrary, the wound closes up, the Amoeba takes in food as 

 before, and the damage is soon completely repaired. How does 

 this affect the individuality of the Amoeba ? Are we still dealing 

 with the same individual? I took away a part of its body, 

 a part of its individuality, which afterwards was replaced by 

 regeneration. No one will contend, because part of the whole 

 body was cut off, that we have no longer before us the same 

 animalcule, that because of the operation we now have to regard 

 the old Amoeba as dead, and that the Khizopod which now 

 crawls about under the microscope is an individual other than 

 the first. With the same right it might be contended that the 



