لأن human subjects والذين كثيرا ما يكونون في حالة صحية سيئة، يخشى الباحثون أن نتائج التجارب مخيبة، وقد تكررت التجارب على البشر حتى على الحيوانات.
Because the human subjects were often in such poor health, researchers feared that the results of the experiments were unreliable, and so human experiments were repeated on animals.