Some people are not easily frightened, others are more readily frightened, and still others are of an extremely fearful nature. It depends upon the proportion of adrenal cortex to medulla secretion in them. And their reaction to fear stimuli is a pretty good measure of the ratio. These formulations apply more particularly to fear in general and anger in general. But even in the least fearsome, i.e., an individual in whom cortex dominates medulla, there may be fear--complexes, dating back to events and times when medulla overtopped cortex, especially childhood. So in the coolest people, certain persons, objects, episodes, may send a wave along an old line of nerve cells and paths which lead to the adrenal medulla, and so flood him with fear, terror or even panic before his usual cortex response occurs. Impressions during the early years of childhood, probing of the unconscious by various methods, have been shown to be the most potent in this respect. Sometimes the episode goes further back than childhood, and one must assume an inherited conditioning of the vegetative and endocrine systems. An animal leaping upon an ancestor in a forest during the night might account for the panic fear some people experience when alone in the dark, that nothing of their childhood history may account for. In women, the adrenal medulla naturally tends to overtop the cortex, because the latter makes for masculinity. Besides, the recurring cycle in the ovary, making the corpus luteum, evolves an additional stimulant to the medulla, through its irritating influence upon the thyroid. Then the influence of the post-pituitary is anti-adrenal cortex. So that, on the whole, a number of endocrines work to render woman naturally fearful, as we say.