It wasn't Kellogg, it was Eichenlaub. The texts are available online at The Wayback Machine, Internet Archive, and Google Books etc. Many other texts, written by physicians, nurses, and other authors who covered many topics are available as well.
I have also read many newspaper articles and columns, that were regularly covering the questions of ordinary people. It is no wonder that our parents and grandparents followed suggestions, recommendations, and orders of the "medical" experts.
I come from a family that had a background in journalistic efforts. Those texts and newspapers were always in abundance around our house. Mom and grandma likely read most of them and with the support of our medical providers, an enema was a very common intervention.
As a teen, I had seen a chiropractor in the neighborhood after a back injury. In addition to massage and manipulation, his assistant and wife advocated colon hydrotherapy. There was no machine, but she accomplished this with a good old fashioned red enema bag.
If bored, peruse the various old texts and see if they don't give rise to our obsessions of the past!