When under the influence of certain (or some) reasons (or causes) (alcohol, war, etc - added Spir here) the low instincts are unbridled (or unrestrained), the brute appears (or come forward, "apparait", Fr. ) and rule over (or dominate), stifling every ("toute", Fr. ) noble, generous impulse; it is then the ruin (or downfall or decline) of any humanity in man.
The trouble with our people is as soon as they got out of slavery they didn't want to give the white man nothing else. But the fact is, you got to give em something. Either your money, your land, your woman or your ass.