said to be so inferior? If they do not enter into the hastily drawn outline, must they be disfigured by submitting them to over-strict theories? Is it not a better plan to acknowledge that old systems are faulty, and that they are not comprehensive enough in _everything_ which they undertake to explain?”[190] The question of intellectual differences, like, indeed, all the other points in anthropological study, has largely exercised the inventive genius of monogenists, for it must be owned that all the efforts of imagination proceed from them. It is not more difficult to admit the development of one or twenty human species upon our planet, than the development of a single moss or sea-weed; they are phenomena of the same order, and equally beyond the actual limits of our knowledge; but this first step taken, anthropology opens itself to the polygenist as simple and easy; he follows, without any trouble, all phenomena, from cause to effect,--everything enters into one general order,--everything is marvellously simple, in spite of apparent complication. It is not the same with the monogenist; ruled continually by his theory, he goes on almost painfully, and at every step some new obstacle is raised to impede his progress. If he thinks he has conquered physical differences, psychological varieties start up; then will arise families of different tongues, quite as radically distinct and as difficult to explain; and yet it is in vain that the obstacle seems so great and insurmountable, it _must_ be overcome, it _must_ be passed in the name of an admitted principle, cost what it may so to do. Thus it is that monogenists have sometimes arrived at the most curious, but at the same time most unfortunate, results.