The Rule against, Perpetuities, as applied to interests in land, may be stated as follows: Any limitation or provision, the purpose or possible effect of which is to cause an estate to commence in the future, is invalid if, as a result thereof, an estate may commence more than twenty-one years after a life or lives in being.

The rule is concerned only with the time of commencement, the vesting, of estates, and not with the duration thereof.71a Accordingly the fact that a life is living, since a son cannot attain thai age more than twenty-one years after the death of his father, a life in being.79

67. 1 Stlmson's Am. St. Law, Sec. 1426. New York, Indiana, Michigan, Wisconsin, Minnesota, California, North Dakota, South Daktoa.

68. 1 Stimson's Am. Law, Sec. 1421. Virginia, West Virginia, Kentucky, Alabama.

69. 1 Stimson's Am. St. Law, Sec. 1424. New York, California, North

Dakota, South Dakota, Georgia.

70. 1 Stimson's Am. St. Law Sec. 1424. New York, Indiana, Michigan, Wisconsin, Tennessee, California, North Dakota, South Dakota.

71. See ante, Sec. 156, note 89a. 71a. That this is the true scope of the rule is conclusively shown in Gray, Perpetuities, Sec.Sec. 123-200, 232estate, limited to arise in the future within the period fixed by the rule, may continue beyond that period, does not affect the validity of the limitation.72

The consideration of policy on which the Rule against Perpetuities may be regarded as primarily based appears to be the desire to facilitate the alienation of property, by prohibiting the clogging of the title for any considerable length of time by a provision for a possible or certain change of ownership in the future. In case there is such a provision, the property can be aliened as a whole only by the consent of the person or persons who have the interest which is liable to be divested in the future, and also of the person or persons in favor of whom the divesting clause is to operate, and since the value of each of these interests is ordinarily, by reason of the uncertainty of the future event named, or of the time of its occurrence, a matter of pure conjecture, the property is in effect to that extent withdrawn from commerce.73 Moreover, the possibility or probability of

246. So in Lewis, Perpetuity, p. 173, it is said: "The remoteness against which the rule is directed is remoteness in the commencement, or first taking, and not in the cesser or determination of them. An estate that is to arise within the prescribed period may be so limited as to be determined on the happening of any event however remote." To the same effect, see Sioux City Terminal R. & W. Co. v. Trust Co. of North America (C. C. A.) 82 Fed. 124; Howe v. Hodge, 152 111. 252; Madison v. Larmon, 170 111. 65, 62 Am. St. Rep. 411, 48 N. E. 924, 38 N. E. 1083; Owsley v. Harrison, 190 111. 235, 60 N. E. 89; Phillips v. Harrow, 93 Iowa, 92, 61 N. W. 434; Pulitzer v. Livingston, 89 Me.

359, 36 Atl. 635; overruling Slade v. Patten, 68 Me. 380; Gambrill v. Gambrill, 122 Md. 653, 89 Atl. 1094; Stewart v. Coshow, 238 Mo. 662, 142 S. W. 283; Philadelphia v. Girard's Heirs, 45 Pa. St. 26; Johnston's Estate, 185 Pa. St. 179, 64 Am. St. Rep. 621, 39 Atl. 879.

72. Gray, Perpetuities, Sec. 232; Madison v. Larmon, 170 111. 65, 62 Am. St. Rep. 356, 48 N. E. 556; Lovering v. Worthington, 106 Mass. 86; Loring v. Blake, 98 Mass. 253; Donohue v. McNichol, 61 Pa. St. 73; Heald v. Heald, 56 Md. 300; In re Boyd's Estate (Pa.) 49 Atl. 297. For an examination of decisions of an opposite tendency, see Gray, Perpetuities, Sec.Sec. 238-246.

73. See Gray, Perpetuities Sec. a change of ownership in the future, without the volition or consent of the present owner, is calculated to affect adversely his readiness or ability to make the most effective use of the property, or to improve it as it is to the public interest that property should he improved.74 This condition of uncertainly of the title, with its attendant disadvantages, is, by the rule referred to, restricted to what the courts have regarded as a reasonable period from the time of its creation.

A limitation or provision which, as providing for the possible commencement of an estate at a time more remote than that fixed by the rule, is originally invalid, is not rendered valid by the fact that, as events turn out, the commencement of the estate must, if it ever occurs, occur within the prescribed period of time, or that it does occur within such period.75

As above stated, it is the possible time of the commencement or vesting of an estate with which the rule is concerned, and consequently, provided the estate cannot vest at an unduly remote period, it is immaterial that the actual possession or enjoyment may be deferred beyond the period of the rule.76