Few if any of the various economic theories that have been advanced, claiming attention in virtue of their practical benefit to the existing conditions of human affairs, have gained so immediate or so widespread an acceptance amongst intelligent persons as that which is familiarly known as "the single-tax" theory propounded by Mr. Henry George. In all parts of the English-speaking world, at least, the theory has obtained many and enthusiastic disciples, who have believed, and probably still believe, that they find in Mr. George's doctrine a panacea for many of the most apparent of the evils which oppress society not less under our advanced civilization than they did at any former period of the world's history. It may be said, indeed, that we hear less of Mr. George and the single tax now than we did a few years ago, and from this some will argue that the idea has died or is dying out of men's minds; this, however, is almost certainly a mistake. In the history of any great system of alleged reform there may be traced at least three distinct stages which are marked by different degrees of prominence in the public regard. The first of these may be called the period of promulgation, the second that of fermentation, and the third that of experiment. If the evils proposed to be reformed are manifest and widely recognized the first of these stages is almost certain to excite wide attention and much controversy on both sides. The earliest stage, that of mere discussion, however, soon wears itself out, and the theorists who argued in favor of, as well as those who argued against, the new system, having exhausted their ingenuity in argument, turn for the most part to something newer, and let the matter drop. Then follows the period of incubation. Removed from the din of controversy a certain number of people are always found who are keenly sensible of the evils which the new system was supposed to cure, and who continue to meditate upon the possibility of its possessing the power to do so. These persons, it may be, make but little noise in the arena either of literature or politics, but they are not the less active, nor perhaps in the end the less really influential, on that account. Their influence is of the sort that depends upon a solid conviction, right or wrong, that the theory which they support is the true one; and as long as the evils, which the system they adhere to professes to cure, continue to exist, so long their influence may be expected to increase. It is the third or experimental stage which is the critical one, and generally speaking it is well when that stage can be reached without any needless delay. By experiment alone can the value of such theories be tested to the satisfaction of the practical mind of humanity, and it is only as the result of a trial that men will either consent to admit the value of a proposed reform or to abandon a specious theory to which they have once given their adherence.