Rollin Hotchkiss, who died December 12 at age 93, was a biochemist and geneticist who helped establish that genes are composed of DNA and who worked on the development of the earliest antibiotics.

Born in South Britain, Conn., Hotchkiss’s parents worked at a local factory that produced animal traps. The family’s limited earnings presented little obstacle to the adventuresome lad, who liked to make pinhole cameras and similar contraptions. After receiving his B.A. and Ph.D. from Yale University, Hotchkiss went to work at the Rockefeller Institute for Medical Research in 1935.

After initially focusing on problems related to proteins and the immune system, Hotchkiss began to work with the microbiologist Rene Dubos on a project that would lead to the development of tyrocidine and gramicidin, the earliest antibiotics.

Until the development of antibiotics, most chemicals used to treat disease were based on poisons such as arsenic, phenols, and heavy metals. Antibiotics were different because they specifically targeted bacteria. “It was the first antibacterial principle that resulted from a deliberate, systematic search for antagonistic principles among soil microorganisms,” Hotchkiss told Science in 1989.

Dubos had been working with various soil microbes. He initially assigned Hotchkiss to the roof of the Rockefeller Hospital building to fractionate “an unpleasant brownish material, incompatible with water, under organic solvents congealing into a sticky substance resembling uncouth ear wax,” Hotchkiss said in the Science interview.

He ended up purifying and crystallizing tyrocidine and gramicidin, allowing their chemical structures to be more completely investigated. The two antibiotics became the first such drugs to be commercially manufactured, although their toxicity meant they were limited to lotions applied to skin. One early beneficiary of gramicidin was Elsie the cow, the Borden mascot, who was cured of mastitis at the 1939 World’s Fair. Later, Hotchkiss attempted without success to get some of the medicine to his mother, who was sick with an ulcer that turned out to be fatal.

During World War II, Hotchkiss served with the medical corps of the U.S. Naval Reserve and developed a popular staining method for detecting polysaccharides in cells and tissues.

In 1946, Hotchkiss began working with Oswald T. Avery, who in 1944 had postulated that DNA was the basic component of genetic material in cells. This stood in opposition to the view of many that genes were composed of some unknown protein. Hotchkiss was able to show that there was no detectable protein in samples of DNA, and also to show that certain traits, such as resistance to sulfa drugs, could be transmitted by DNA.

Hotchkiss also was a pioneer in using chromatography to identify the organic bases purine and pyrimidine.

He stayed at Rockefeller his entire career, having been promoted to professor in 1955. He retired as an emeritus professor in 1982 and later held an appointment as a research professor at SUNY Albany, not far from his retirement home at Lenox, Mass.

A man of committed enthusiasm, Hotchkiss was especially enamored of gemstones and frequently took his family on mineral collecting trips. Later, he would polish and cut the stones. He also worked with stained glass and practiced cabinet-making and photography. He served as a volunteer usher at Tanglewood until nearly the end of his life.

Hotchkiss was the author of more than 150 scientific articles. In 1961, he was elected to the National Academy of Sciences, and he was also an honorary member of the Hungarian Academy of Sciences and the Royal Danish Academy of Sciences.

Rollin Hotchkiss

Born September 8, 1911, in South Britain, Conn.; died December 12 at his home in Lenox, Mass.; survived by his wife, Magda Gabor-Hotchkiss; his children, Paul Hotchkiss and Cynthia Hotchkiss Lydgate, three grandchildren, and five great-grandchildren; he is also survived by his first wife, Shirley D. Hotchkiss, from whom he was divorced in the 1960s.