246. X. THAT THE EXTERNAL CAUSES OF COLD ARE ALSO MANY, AND OF THESE THE FIRST IS DISSIMILITUDE IN ANIMUS AND MANNERS.
Similitudes and dissimilitudes are internal and external. The internal take their origin from no other source than religion; for this is implanted in souls, and through souls is derived from parents to offspring as a supreme inclination. The soul of every man derives its life from the marriage of good and truth, and from this marriage is the Church; and because the latter is various and diverse in different parts of the globe, the souls of all men are likewise various and diverse. From this source, therefore, come the internal similitudes and dissimilitudes and the consequent conjugial conjunctions here treated of.
 External similitudes and dissimilitudes are not predicated of the soul but of the animus. By the animus is meant external affections and the inclinations therefrom. After birth, these are insinuated chiefly by education, associations with others, and the resultant habits; for when one says, "I have a mind (animus) to do this or that," his affection is perceived and his inclination to that thing. Moreover, the animus is usually formed by accepted persuasions concerning this or that kind of life. Hence come inclinations to enter into marriage even with unequals, and also to refuse entering into marriage with equals. Yet, after the partners have lived together for a time, these marriages vary according to the similitudes and dissimilitudes contracted from heredity and at the same time by education, the dissimilitudes inducing cold.  So likewise dissimilitudes in manners, as, for example, in the marriage of an uncultured man or woman with a refined man or woman; of a cleanly man or woman with an uncleanly; of a quarrelsome man or woman with a peaceable; in a word, of an ill-bred man or woman with a well-bred. Marriages of such dissimilitudes are not unlike conjunctions of different kinds of animals which do not consociate because of their dissimilitudes; as of sheep and goats, of stags and mules, of hens and geese, of sparrows and noble birds, yea, of dogs and cats. In the human race, faces do not indicate these dissimilitudes but habits. Therefore, from this source come colds.