In the present communication I propose to consider the nature of the excitation processes mediating the thoughts of people, met with in all walks of life, who are distinguished from others by their enthusiasm for certain things, or ideas. For example, the person in love is distinguished from others by his, or her, enthusiasm for a particular individual of the opposite sex. The process of developing that enthusiasm, or of falling in love, I take to be a perfectly natural process to which everyone is susceptible, but, love being blind, it becomes of interest to consider how that blindness is brought about.