272 FERTILIZATION OF FLOWERS BY INSECTS. 
been perpetuated, owe it to the circumstance that, in the struggle 
for existence, they were advantageous to those individuals in which 
they appeared. From the Darwinian doctrine, then, there springs 
the following thesis, which is of general application; that in all 
animals and in all plants there is not a single characteristic, a single 
property, which is not either useful to its possessor, or at least is not 
inherited from ancestors more or less remote, for whom, at some time, 
it procured a decided advantage in the battle of life. 
Therefore, if we wish to apply the Darwinian doctrine to the 
rich and varied kingdom of Flora, we should, in the first place, 
answer this question: in what manner and by what means have 
the brilliant colors, the diverse odors, and the variegated structure 
of their flowers been of use to plants? The solution of this ques- 
tion cannot be obtained from a consideration of the flowers alone, 
for their properties are not immediately useful, but only mediately ; 
and the mediation is accomplished by insects. 
That flowers are visited by insects in various ways, and that 
many of them— bees, for example—are constrained to visit them 
for food, is well known; but this fact does not suffice to explain 
how these visits can be advantageous to the plants. Colors, 
odors, pollen, and honey seem at first sight to be of utility only to 
insects. If, as did C. C. Sprengel towards the close of the last 
century, we should propose to consider how insects act upon plants, 
and the wonderful. conformity of floral structure which certain 
plants have with certain insects, we, like Sprengel, would easily 
fall into the belief that such harmonies are the cause of the insects 
effecting, without either knowing or willing it, the transfer of pol- 
len from the anthers to the stigmas, while seeking their food in the 
flowers. But why should nature have entrusted to insects the 
but can 3 no away admit that the causes of these variations were only determinate 
chemico- For who has eyer been able to determine them, and who will 
ever be able? I should — woud = the causal princi ple of these variations is an 
intrinsic and not: external one p p hole of life 
ing to 
deny the action or influence of external ci reums tances; but I think that crn as long 
as life lasts, and within rtain limits, are ruled over byt hat internal principle, intelli- 
gent and free, which I candi idly seat that uy 
mode of thinking i is purely and simply theoretical; but th the sara rary thesis mainta 
by Miiller and all the naturalists of our age, is ran Toe and simply sbbondeteet ‘asi 
soon wil be! and theory for paramo I prefer m. 
f the tw 
the 
victory, I think I do not err in saying that the question iy: ana always has been insol- 
