Although discrimination between odors is largely a matter of training, reflex paths for affective reactions to olfactory stimuli are formed before birth, as is evidenced by observations on infants within the first hour after birth, such as are described by Preyer and others. Observations on animal behavior, as well as medical experience, and the history of perfumery, furnish further abundant evidence of inborn (racial) likes and dislikes to odors and of required predilections. Each individual manifests certain reactions to different olfactory stimuli based on racial and individual experience, the sum total of his likes and dislikes to odors forming an olfactory affective syndrome on diathesis expressive and characteristic of his individuality.

It would appear desirable to undertake experiments on a very large scale with subjects of widely different racial origin, Indians, Chinese, Negroes, Jews, etc., and an extensive scale of different odors to obtain the mean olfactory syndrome characteristic of the race, and to endeavor to correlate the affective judgments obtained with metabolic characteristics such as endocrine balance, pigmentation, and sex differences.

This olfactory syndrome is liable to fluctuate and be modified by various factors, such as familiarity with an odor, but particularly by changes in metabolic conditions, such as menstruation and pregnancy, and disease. The syndromes revealed by the present experiments may be studied by a perusal of the following tables, and the relative constancy, as well as the modifications in the affective judgment be seen in some of the cases.