"John Brown's Body"

NOT the William P. McGivern/David W. O'Brien story. This short story had Brown colonized with helpful microbes (from the days before nanites) that did him all sorts of good, however sometimes they decided what his good would be, independent of his 'druthers—-so they would keep him from drinking alcohol or induce him to be aroused by a woman that the microbes themselves wanted to colonize. Probably from the late '60s through the '70s. Thanks.