When I was no more than a boy and beginning to show some interest in living creatures I can remember being sternly warned by my elders to beware of the dangers of analogies. It was said in the same tone one might tell someone not to eat a certain kind of mushroom. I do not believe it ever seriously curbed my instinct for analogy; I went on comparing as any person will whether it be consciously or unconsciously, but the feeling of slight guilt has always remained and is no doubt now responsible for my writing this short essay.