Marshall, J.

Was it competent for the supervisors of the towns of Greenfield and Wauwatosa to burden the consent granted to the street railway company with conditions ? That is the principal question to be considered on this appeal. If it must be answered in the affirmative, evidently the conditions might extend to regulations in respect to preserving and maintaining the highways in a suitable condition for public travel, which, in our opinion, according to the logic of State ex rel. Milwaukee v. Milwaukee E. R. & L. Co. 151 Wis. 520, 139 N. W. 396; Madison v. Southern Wis. R. Co. 156 Wis. 352, 146 N. W. 492; and State ex rel. Milwaukee v. Milwaukee E. R. & L. Co. 165 Wis. 230, 161 N. W. 745, would include such requirements as the one complained of, and that there is nothing in La Crosse v. La Crosse G. & E. Co. 145 Wis. 408, 130 N. W. 530, inconsistent therewith. So if we reach the conclusion that the supervisors were competent to so burden their consent, it would be useless to go further and discuss other propositions suggested in the briefs of counsel.

The case really comes down to what was the purpose of the legislature in prohibiting the use of highways in any town for street railway purposes except upon condition precedent of consent being first obtained in writing of a majority of the board of supervisors of such town.

Counsel for appellants contend that the statute does not confer upon supervisors, in the circumstances under consid*182eration, any authority to burden their consent with terms. Unless there be some clear indication in the statute- to the contrary, there can be little, if "any, doubt but what the requirement of consent was for some important purpose having reference to preservation of the highways in a suitable condition for public use. It is insisted that there is such indication in that the requirement for consent'as to towns is closely connected with the requirement as to villages and that, whereas the statute is silent as to terms of the consent in respect to the former, they are expressly provided for as to the latter. In that situation it is insisted that the maxim “Ex-pressio unius est exclusio alterius” applies. The doctrine of express mention and implied exclusion is a mere rule of statutory construction to be applied, or not, in determining the legislative intent, according to circumstances. It is not an arbitrary rule. It has no application except to aid in solving uncertainty, and where there is such uncertainty it will aid very much or very little or not at all in solving it, according to the situation dealt with. It should never be applied so as to defeat a plain legislative purpose. That is well stated in Black on the Interpretation of Laws (2d ed.) 219, thus:

“The maxim 'Expressio unius est exclusio alterius’ is of very important, though limited, application in the interpretation of statutes. It is based upon the rules of logic and the natural workings of'the human mind. But it is not to be taken as establishing a Procrustean standard to which all statutory language must be made to conform. On the contrary, it is useful only as a guide in determining the probable intention of the legislature, and if it should be clearly apparent, in any particular case, that the legislature did not in fact intend that its express mention of one thing should operate as an exclusion of all others, then the maxim must give way.”

So, though the rule is a very valuable one and of frequent application, it is always to be applied with caution, keeping *183in mind that its sole purpose is to aid in searching for the real intention •which the language in question was used to express. Swick v. Coleman, 218 Ill. 33, 40, 75 N. E. 807; Grubbe v. Grubbe, 26 Oreg. 363, 370, 38 Pac. 182.

There is no more familiar rule to be resorted to in the construction of statutes than that the reason and spirit of the enactment are to he considered. Harrington v. Smith, 28 Wis. 43. Row the condition precedent of consent of a majority of the hoard of supervisors must, as before suggested, have been intended to serve some purpose with reference to preservation of the public ways for ordinary use. It implies that the legislature intended the 'circumstances of each situation to be considered and that the supervisors would exercise some discretion, having reference thereto, and grant the consent on such terms as would, in their judgment, satisfy the particular situation. The idea that the requirement does not serve any purpose at all, is so unreasonable that wo cannot adopt it. It seems contrary to reason and authority.

As indicated in the brief of counsel for respondent, Judge Elliott at sec. 1081, vol. 3 (2d ed.), of his work on Railroads, carefully considered this subject and, upon reason and authority, came to the conclusion we have reached and thus expressed his views: /

“Where a municipal corporation has power to grant or refuse a railway company the right to use its streets 'as it sees fit,- or where consent is required before any company can use them, it has, we think, authority to prescribe the terms and conditions upon which the company shall have the right to construct and operate a railway in its streets.”

We approve of that and are of the opinion that the legislature, having made the consent to use the highways a condition precedent, shows so clearly an intention to confer upon the supervisors authority to burden the consent with reasonable terms to conserve the public welfare, that the maxim relied on by counsel for appellants has no application. It *184must give way to the obvious purpose of tbe lawmakers to empower tbe supervisors to burden tbeir consent with conditions which, as before stated, according to the logic of our previous decisions, includes authority to require the doing of such things as were required in the particular instance.

What has been said is in harmony with Manitowoc v. Manitowoc & N. T. Co. 145 Wis. 13, 129 N. W. 925, where several well considered cases are referred to holding that when consent of a municipality is a condition precedent to the use of its streets for railway purposes, such consent may be burdened with such reasonable terms as the public welfare, in the judgment of the authorities empowered to deal with the matter, require, having regard, of course, to legislative purpose.

It does not seem best to further discuss the case. More could not well be said to show that the right of reserving the consent includes authority to make such regulations of the use of the street as those complained of, than was said of quite similar regulations in Madison v. Southern Wis. R. Co. 156 Wis. 352, 146 N. W. 492. The language used here was very broad and comprehensive. It was to “make such reasonable regulations as the public safety or convenience may require.” That limitation was in connection with the obligation of the railway company to “keep in good and thorough repair at its own cost and charge” its track zone. The consent was for a very long term which was given much significance in the Madison Case in determining the scope of the power reserved to the municipality and the duty assumed by the railway company, indicating that the duty to repair had reference not only to present but the reasonable requirements of changed conditions. The terms of the consent were as binding as like terms would be in any franchise. This court in State ex rel. Milwaukee v. Milwaukee E. R. & L. Co. 151 Wis. 520, 139 N. W. 396, and Madison v. Southern Wis. R. Co., supra, adopted as a rule for this state the *185doctrine deduced by Judge Elliott in his work on Roads & Streets, vol. 2 (3d ed.), at secs. 987, 988, from many authorities. This, as stated in the Madison Case:

“Where the franchise granted to build, maintain, and operate a street-car system contains an express requirement to repair, it continues with the life of the grant, creating a duty of such performance as will make that portion of the tract to which it relates conform to the changes outside thereof, made from time to time under the direction of the municipality in order to render the way suitable for public use, and such performance includes, in making repairs, after repaying by the municipality with the same material as before, and repaving by substitution of a different material to conform to this changed condition as well.”

So it will be seen that having reached the conclusion that the terms of the consent given to the railway company were properly imposed, the requirement complained of must be held to be within such terms.

By the Court. — The judgment is affirmed.