THE ARGUMENT IS THAT, BECAUSE NO HUMAN BEING MAY BE USED IN A MEDICAL EXPERIMENT WITHOUT HIS OR HER INFORMED, FREELY GIVEN CONSENT, AND BECAUSE PRISONERS BY VIRTUE OF THEIR CUSTODY CANNOT GIVE SUCH CONSENT, PRISONERS MUST BE EXCLUDED FROM ALL MEDICAL EXPERIMENTATION, REGARDLESS OF HOW VALUABLE SUCH EXPERIMENTATION MIGHT PROVE. THE ARGUMENT IS FORCEFUL BUT NOT PERSUASIVE. ITS KEY PREMISE IS MISTAKEN. A WIDE SENSE OF CONSTRAINT (WHICH CORRECTLY CHARACTERIZES THE PRISON ENVIRONMENT) IS CONFUSED WITH A DIFFERENT, NARROWER SENSE OF CONSTRAINT INVOLVED IN THE DECISION TO PARTICIPATE IN A MEDICAL EXPERIMENT. IT IS POSSIBLE FOR THE PRISONER TO BE ENTIRELY FREE OF THIS NARROWER TYPE OF CONSTRAINT. IN THE SENSE THAT ONE IS COERCED BY ONE'S CONDITION, EVERYONE IS COERCED--MANY AS SEVERELY AS OR MORE SEVERELY THAN PRISONERS. IN THE SENSE THAT, GIVEN ONE'S CONDITION, ONE CAN MAKE CHOICES WITHOUT ULTERIOR MANIPULATION IN VIEW OF THE MERITS OF THE MATTER BEING DECIDED, PRISONERS CAN, IF FAIRLY TREATED, BE AS FREE TO CHOOSE AS ANYONE ELSE. PRISONERS AND NONPRISONERS ALIKE MUST BE CAREFULLY PROTECTED AGAINST FORCE, FRAUD, DECEIT, DURESS, AND OTHER MANIPULATION IN MAKING THEIR CHOICE. IN THE CASE OF PRISONERS, THE FACT OF TOTAL CUSTODY AND THE EVIDENT POTENTIAL FOR ABUSES OF POWER PLACE STRINGENT DEMANDS ON THOSE RESPONSIBLE FOR ENSURING THAT PROTECTION. THE COMMON ARGUMENT FOR AUTOMATICALLY EXCLUDING PRISONERS FROM EXPERIMENTATION, BASED AS IT IS ON A MISUNDERSTANDING OF WHAT IS REQUIRED FOR GENUINELY FREE CONSENT, IS WEAK. THE EXCLUSIONARY RULE THAT IS A PRODUCT OF THE ARGUMENT DENIES PRISONERS THEIR RIGHT TO GIVE OR WITHHOLD CONSENT AND IGNORES THE WORTH OF MEDICAL EXPERIMENTATION IN WHICH PRISONERS PARTICIPATE OF THEIR OWN VOLITION. A LIST OF REFERENCES IS INCLUDED. (LKM)