Throughout thls article, the author revlews the implications which on the part of human nature are compromised by the fact of experimentation with man. These natural conditlons can not be overlooked nor set aside by the researcher; to do so would entail the grave effect of making the whole experimental work sterile. The concept of Iimit is studied here from both the scientiflcal and methodological points of view, staving off thus possible paradoxes which have been organized with regard to this concept in certain scientific circles in today's society. Further on, the author puts forth the dlfferent relationships which are to be found between the nature of investigation and the investigation of natura, maklng explicit the relations of dependency and of convergence which exlst between the twO. After bringlng to the light the new editions of erratic cartesianism (Biocracy and Psychocracy) which are based upon an abundant bibliographical foundation which is very up-to-date. the author ends thls paper by proposing the necessity of establishing acode of laws on human research which would arbitrate and regulate the relations between the experimenter and the patients who submit themselves to research, as well as the circumstances under which such experimentatlon should take place.