402 Death not Universal P [July, 
That this may be understood we must briefly compare the 
life-history, and especially the reproduction, of the Metazoa 
and the Protozoa . In the former group — which includes all 
the back-boned animals from man down to the humblest 
fish, all the insects, mollusks, as well as lower forms of life 
which scarcely attract popular notice — there is always a 
distinct difference between parent and offspring. The latter 
is certainly a portion separated from the body of the parent, 
—from the female in all those forms in which there exist 
two sexes, — but it is as compared with the parent minute in 
size, rudimentary in structure, and it has to increase in bulk, 
and still more to undergo a process of development, a series 
of transformations, before it reaches the normal stature and 
make of its species. When this point has been attained it 
enters upon the task of reproduction, and gives birth to one 
brood of young ones, or in the higher forms to several. 
With these it co-exists for a longer or shorter time, and then 
dies, the matter which constituted its body passing into de- 
composition. If we look at these very familiar facts in the 
life of a Metazoon, be it a man or an oyster, we find that the 
ideas of birth, of growth, of maturity, of parenthood, of a 
natural term of life ending in death, at once suggest them- 
selves. If we examine such a Metazoon we can, in most 
cases, at once decide whether it is in the immature or the 
adult phase of its being. 
But in the Protozoa — as Herr Butschli has not long ago 
pointed out in the “ Zoologischer Anzeiger ’’—this is dis- 
tinctly different. 
Let us suppose we are watching through a microscope 
one of these minute single-cell creatures. We see it ex- 
panding into an ellipsoidal figure, which becomes for a time 
longer and longer. It then begins to contract about what 
we may, for the sake of popular intelligibility, call its equator. 
It assumes the form of two nearly globular bodies, con- 
nected, dumb-bell like, by a narrow neck. This neck becomes 
narrower and narrower, and at last the two globes are set 
free, and appear as two individuals in place of one ! What 
are the relations of these two new beings to the antecedent 
form and to each other ? We examine them with care ; they 
are equal in size, alike in complexity, or rather simplicity, of 
structure. We cannot say that either of them is more ma- 
ture or more rudimentary than the other. We can find in 
their separation from each other no analogy to the separation 
of the young animal or the egg from its mother, or to the 
liberation of a seed from a plant. Neither of them is parent, 
and neither offspring. Neither of them is older or younger 
than the other. 
