Man by nature is endowed with the talent of devising means to remedy or prevent the evils that are liable to arise from gratifying our appetites; and it is as much the duty of the physician to inform mankind of the means to prevent the evils that are liable to arise from gratifying the productive instinct as it is to inform them how to keep clear of the gout or dyspepsia. Let not the old ascetic say we ought not to gratify our appetites any further than is necessary to maintain health and to perpetuate the species. Mankind will not so abstain, and if any means to prevent the evils that may arise from a farther gratification can be devised, they _need not_. Heaven has not only given us the capacity of greater enjoyment, but the talent of devising means to prevent the evils that are liable to arise therefrom, and it becomes us, "with thanksgiving," to make the most of them. FRUITS OF PHILOSOPHY. CHAPTER I. TO LIMIT AT WILL THE NUMBER OF THEIR OFFSPRING Showing how desirable it is, both in a political and a social point of view, for mankind to be able to limit at WILL THE NUMBER OF THEIR OFFSPRING, WITHOUT SACRIFICING THE PLEASURE THAT ATTENDS THE GRATIFICATION OF THE REPRODUCTIVE INSTINCT. First.---_In a political point of view_.--If population be not restrained by some great physical calamity, such as we have reason to hope will not hereafter be visited upon the children of men, or by some _moral restraint_, the time will come when the earth cannot support its inhabitants. Population unrestrained will double three times in a century. Hence, computing the present population of the earth at 1,000 millions, there would be at the end of 100 years from the present time, 8,000 millions. At the end of 200 years, 64,000 millions. " " 300 " 512,000 " And so on, multiplying by eight for every additional hundred years. So that in 500 years from the present time there would be thirty-two thousand seven hundred and sixty eight times as many inhabitants as at present. If the natural increase should go on without check for 1,500 years, one single pair would increase to more than _thirty-five thousand one hundred and eighty-four_ times as many as the present population of the whole earth!