237. III. THAT THE CAUSES OF COLD IN THEIR SUCCESSIONS ARE MANY, SOME INTERNAL, SOME EXTERNAL, AND SOME ACCIDENTAL. That there are many causes of cold in marriages is known in the world; and also that cold arises from many external causes. But that the origins of these causes lie concealed in man's inmost parts, and that from these they betake themselves into the parts that follow, until at last they appear in externals, is not known. In order, therefore, that it may be known that the external causes are not causes in themselves but are derived from causes which are causes in themselves and which, as was said, are in man's inmosts, the causes are first divided generally into internal and external, and are then examined in detail.