440 TOWER, DARWINISM. 
31,450 entered’ into hibernation and 25,714 emerged. The combined 
result. of these tests made on the savannahs of Vera Cruz, in the 
mountainous groups of the Mexican plateau at Cuernavaca and in the 
temperate regions of southwestern Michigan with different species 
under different but natural habitats showed uniformly that survival in 
these organisms during the principal eliminating period of their lives is 
due to favorable position and conditions rather than to favorable 
constitution. 
DISCUSSION AND CONCLUSION. 
In three species of plants, 520,000 seeds tested showed that under 
natural conditions 10,335 out of 260,000 germinated, while under 
favorable conditions 228,742 out of 260,000 germinated. In four 
species of animals 172,140 tested gave 67,977 surviving out of 
86,070, under favorable conditions; and 5,709 out of 86,070 under 
natural conditions of aestivation. In a total of 692,140 organisms 
tested, 16,044 survived out of 346,070 under natural conditions; 
and 296,719 out of 346,070 under favorable survival complexes. Unal- 
tered normal habitats evidently afford abundant eliminating activities 
based, as in these tests, upon chance position. The only altered 
factor in these tests was the one that made favorable conditions 
in half the experiment during the phase of the life cycle where 
large elimination naturally takes place. 
The relations of organisms in their native habitats are evidently 
extremely complex and the forces that determine elimination or 
survival are constantly present, so that each succeeding moment is 
a repetition of the test of the interactions between organisms and 
environing forces which might eliminate them. Although this is 4 
constant relation, it is also evident that elimination occurs more 
frequently and in greater numbers at certain stages in the life of 
the organism that at others, and it is in these critical periods 
that the great reductions in the numbers of each generation take 
place. Consequently, these stages are the most profitable places 
to examine the problem of survival and elimination, because there 
we may expect to find in the most readily detachable and analyzable 
form whatever is happening in the way of eliminations and whether 
survivals have selective or adaptive trends. 


