As you report, John Coats and Joe Herbert of Cambridge University have showed that two hormones, testosterone and cortisol, both of which are linked with mood and behavior, explain a good deal of what financial traders do (“Bulls at Work,” April 19, 2008). Among many other things, testosterone is associated with winning and losing, while cortisol is associated with stress. “The upshot is that financial traders seem less stressed by failure than uncertainty,” you conclude. “That is probably a realistic response to the nature of the job.” Well, that is undoubtedly a realistic response to the nature of sentient life in general. Any writer worthy of that title would be surprised that endocrinology is needed to come up with a truism of this ilk.