Conversation so far:
What medical breakthroughs did John Harvey Kellogg make?
Did John Harvey Kellogg invent any new equipment?
John Kellogg invented a hot air bath, vibrating chair, oscillomanipulator, window tent for fresh air, pneumograph to graphically represent respiratory habits, loofah mitt, and apparatus for home sterilization of milk.
How old was John Harvey Kellogg when he started studying medicine?
At age 20, The Kelloggs and the Whites convinced John Kellogg to join a six-month medical course at Russell Trall's Hygieo-Therapeutic College in Florence Township, New Jersey.
What information can you give me about John Harvey Kellogg's inventions?
John Kellogg invented medical equipment, phototherapeutic therapy, electrotherapeutic therapy, mechanical massage devices, and a colon irrigator.
Did John Harvey Kellogg invent any medicines or only equipment?
John Harvey Kellogg developed and marketed a wide variety of vegetarian foods, besides inventing medical equipment, phototherapeutic therapy, electrotherapeutic therapy, mechanical massage devices, and a colon irrigator.
What foods did John Harvey Kellogg invent?
John Kellogg developed and marketed a wide variety of vegetarian foods. He invented corn flakes, peanut butter, imitation meats, and the first acidophilus soy milk.
What year did John Harvey Kellogg start inventing tools for medical procedures?
Many of the machines invented by John Kellogg were manufactured by the Battle Creek Sanitarium Equipment Company, which was established in 1890.

Question: What year did he die?
Self-contained rewrite: What year did John Harvey Kellogg die?