Dr. Kenneth Drake Gardner, a San Francisco doctor for half a century, died last Thursday at the age of 85.

The son of a gold miner, Dr. Gardner moved to California in the early 1900s from his native Portland, Ore. His brother, Erle Stanley Gardner, was the creator of Perry Mason, writing more than 250 books and television episodes about the fictionalized attorney.

After graduating from Oakland High School in 1919, Dr. Gardner earned his undergraduate degree from Stanford in 1923. In 1927, he graduated from Stanford Medical School and interned at Highland-Alameda Hospital.

In 1928, he entered practice, specializing in internal medicine. Dr. Gardner retired from his practice, which was on Van Ness Avenue for several decades, in 1978.

Dr. Gardner was a past president and a former council member of the Irwin Memorial Blood Bank in San Francisco. He was also one of the original members of the American Society of Internal Medicine.

Dr. Gardner was also a member of the Palo Alto Masonic Lodge for 64 years and had belonged to the Pacific Union Club since 1941.

He is survived by his wife, Dorothy Gardner, of San Francisco; a son, Kenneth Gardner, of Albuquerque, N.M., and four grandchildren.

Private services are planned. Donations are preferred to the Irwin Memorial Blood Bank, 270 Masonic Avenue, San Francisco 94118.