Scientific ethics

Pesic's Labyrinth states "Bacon relies on what is most revered and 'natural' to moderate the disorienting effects or altering nature" and that "he aniticipates an alliance [of science] with Christian humanism" which would "weaken if Christianity or classical learnign were to decay." pg. 55

In The New Atlantis, Bacon describes rather radical forms of experimentation, using"poisons and other medicins upon [animals]" to "find means to make commixtures and copulations of different kinds" pg. 263.

What is this 'natural' standard by which scientists are to define what is acceptable or not in terms of modifying nature and its creatures? And who is in charge of establishing it? It seems the humanism Bacon relies on to solve the ethical and moral questions on experimentation is rather unsteady ground, depending on the shift of social thought. It seems that this kind of experimentation is endorsed by the divine, according to the legend of how the New Atlantis developed, but where does Bacon draw the line on what forms of experimentation are acceptable or not? And where would he expect others to draw it? What happens if Christian humanism does decay?