¶ Just as you can not understand the meaning of a word until you know the letters that go into the makeup of that word, you cannot analyze people accurately until you get these five extreme types firmly in your mind, for they are your alphabet. Founded in Five Biological Systems ¶ Each PURE type is the result of the over-development of one of the five biological systems possessed by all human beings--the nutritive, circulatory, muscular, bony or nervous. Therefore every individual exhibits to some degree the characteristics of all the five types. The Secret of Individuality ¶ But his PREDOMINANT traits and INDIVIDUALITY--the things that make him the KIND of man he is--agree infallibly with whichever one of the five systems PREDOMINATES in him. Combinations Common in America ¶ The average American man or woman is a COMBINATION of some two of these types with a third discernible in the background. To Analyze People ¶ To understand human beings familiarize yourself first with the PURE or UNMIXED types and then it will be easy and fascinating to spell out their combinations and what they mean in the people all about you. Postpone Combinations ¶ Until you have learned these pure types thoroughly it will be to your advantage to forget that there is such a thing as combinations. After you have these extreme types well in mind you will be ready to analyze combinations. The Five Types ¶ Science has discovered that there are five types of human beings. Discarding for a moment their technical names, they may be called the fat people, the florid people, the muscular people, the bony people and the mental people. Each varies from the others in shape, size and structure and is recognizable at a glance by his physique or build. This is because his type is determined by the preponderance within his body of one of the five great departments or biological systems--the nutritive, the circulatory, the muscular, the bony or the nervous. At Birth ¶ Every child is born with one of these systems more highly developed, larger and better equipped than the others. Type Never Disappears ¶ Throughout his life this system will express itself more, be more intense and constant in its functioning than the others and no manner of training, education, environment or experience, so long as he remains in normal health, will alter the predominance of this system nor prevent its dictating his likes, dislikes and most of his reactions. Effect of Eating ¶ If you do not understand why the overaction of one bodily system should influence a man's nature see if you can't recall more than one occasion when a square meal made a decided difference in your disposition within the space of thirty minutes.