It is no sign that affections have the nature of true religion, or that they have not, that they have great effects on the body. All affections whatsoever, have in some respect or degree, an effect on the body. As was observed before, such is our nature, and such are the laws of union of soul and body, that the mind can have no lively or vigorous exercise, without some effect upon the body. So subject is the body to the mind, and so much do its fluids, especially the animal spirits, attend the motions and exercises of the mind, that there cannot be so much as an intense thought, without an effect upon them.