Triffids were at large . Sometimes I saw them crossing fields or noticed them inactive against hedges . In more than one farmyard they had found the middens to their liking and enthroned themselves there while they waited for the dead stock to attain the right stage of putrescence . I saw them now with a disgust that they had never roused in me before . Horrible alien things which some of us had somehow created , and which the rest of us , in our careless greed , had cultured all over the world . One could not even blame nature for them . Somehow they had been bred - just as we had bred for ourselves beautiful flowers or grotesque parodies of dogs ..。. I began to loathe them now on account of more than their carrion - eating habits - for they , more than anything else , seemed able to profit and flourish on our disaster ... Commentary : This novel is a warning about the dangers ofgenetic engineering . The creation of new types of plant ( and animal ) can potentially unleash unpredictable