The Harvard affiliates involved in the Wrenthamexperiment were Dr. Kirshna M. Saxena, a Harvardresearch fellow, and Dr. Earle M. Chapman, anassistant professor of clinical medicine at theMedical School.

Dr. Charles V. Pryles, director of medicalservices at the Wrentham school and an affiliateof the Boston University School of Medicine, alsoparticipated in the tests.

Chapman died in 1990, Saxena has moved toMinnesota and Pryles has not been located, Harvardofficials said yesterday.

Saxena did not return a phone call to his home.

A preliminary review suggests that Saxena wasnot particularly interested in the research, whichwas not in his primary field of study, accordingto Corlette But Corlette added that the researchfellow had free time and was willing to assist.

The scientists gave 63 children at Wrentham adaily dose of radioactive sodium iodine rangingfrom 100 to 1000 micrograms. In the publishedstudy, the researchers called the children"mentally defective."

"We chose this population of children becauseit was desirable to secure children living underconstant conditions of environment, diet anduptake," the researchers wrote in the study, whichwas carried out between December 14,1961 and April14,1962.

The experiment examined the possibility ofincreasing the body's ability to absorb theeffects of nuclear fallout by administeringsmaller doses to increase tolerance levels. Thechildren were grouped into three age categoriesfor the test.

Michael Whalen, a Harvard physicist who worksat the University's Department of EnvironmentalHealth and Safety, said the effect of theradioactive iodine would depend on the isotope'sconcentration.

High concentrations of the idodine-131 used inthe experiment can lead to thyroid cancer, Whalensaid.

"It's not something you really want to do,"Whalen said. "Personally, I probably wouldn't doit."

Whalen called the experiment "just one more ofthose experiments of the 1960s and 1950s thatyou've been reading about."

Government approval for the study was obtainedlikely because of Cold War fears about the dangersposed by nuclear fallout.

"The release of radioactivity into theatmosphere from nuclear explosions in the recentpast has created an acute awareness of the problemof human protection from such radiation," thestudy says. "Radioactive iodine is one of theprinciple contaminants in fallout."

Misilo said the current investigation isimportant because such tests should not to bereplicated.