— This appeal presents a single issue; Does.the title to chapter 77, Laws of 1963, p. 476, “An Act providing for the registration of contractors; and prescribing penalties,” violate article 2, § 19, of the state constitution, “No bill shall embrace more than one subject, and that shall be expressed in the title”?
*489The trial court held that the act was unconstitutional for the reason that “The bonding provisions in Section 4 of said law and the insurance provision in Section 5 of The Act are not germane or related to the subject of registration.”
The questioned act contains 12 sections. Section 1 defines the term “contractor.” Section 2 requires the contractor to procure a certificate of registration from the Department of Licenses before engaging in the contracting business, and provides penalties for violation. Section 3 prescribes the information the contractor must furnish to the department in his application for registration, prior to issuance of the certificate. Section 4, p. 477, provides:
Each applicant shall, at the time of applying for a certificate of registration, file with the director of licenses a surety bond running to the state of Washington if a general contractor, in the sum of two thousand dollars; if a specialty contractor, in the sum of one thousand dollars, conditioned that the applicant will pay all taxes and contributions due to the state of Washington, and will pay all persons furnishing labor or material or renting or supplying equipment to the contractor and will pay all amounts that may be adjudged against the contractor by reason of negligent or improper work or breach of contract in the conduct of the contracting business. Any person having a claim against the contractor for any of the items referred to in this section may bring suit upon such bond in the superior court of the county in which the work is done or of any county in which jurisdiction of the contractor may be had. A copy of the complaint shall be served by registered or certified mail upon the director of licenses at the time suit is started and the director shall maintain a record, available for public inspection, of all suits so commenced. Such service shall constitute service on the surety and the director shall transmit the complaint or a copy thereof to the surety within forty-eight hours after it shall have been received. The surety upon the bond shall not be liable in an aggregate amount in excess of the amount named in the bond, but in case claims pending at any one time exceed the amount of the bond, claims shall be satisfied from the bond in the following order:
(1) Labor, including employee benefits;
(2) Taxes and contributions due the state of Washington;
*490(3) Material and equipment;
(4) Claims for breach of contract.
In the event that any final judgment shall impair the liability of the surety upon the bond so furnished that there shall not be in effect a-bond undertaking in the full amount prescribed in this section, the director shall suspend the registration of such contractor until the bond liability in the required amount unimpaired by unsatisfied judgment claims shall have been furnished.
In lieu of the surety bond required by this section the contractor may file with the director a cash deposit or other negotiable security acceptable to the director.
In the event of a judgment being entered against such deposit, the director of licenses shall upon receipt of a certified copy of a final judgment, pay from the amount of the deposit said judgment.
Section 5, p. 479, provides:
At the time of registration the applicant shall furnish to the director satisfactory evidence that the applicant has procured and has in effect public liability and property damage insurance covering the applicant’s contracting operations in the sum of not less than twenty thousand dollars for injury or damage to property and fifty thousand dollars for injury or damage including death to any one person and one hundred thousand dollars for injury or damage including death to more than one person.
In the event that such insurance shall cease to be effective the registration of the contractor shall be suspended until such insurance shall be reinstated.
Section 6 authorizes the Director of Licenses to issue a certificate for one year upon compliance with the provisions of the act. Section 7 prescribes the fees to be paid for registration. Section 8 requires a certificate of registration as a prerequisite to commencing an action in any court to recover for the performance of work as a contractor. Sections 9 and 10 grant certain exemptions. Section 11 is the severability clause, and § 12 declares the effective date of the act.
In adjudicating the sufficiency of the title to a legislative enactment, we have adhered to the following general rules:
*491The title to a bill need not be an index to its contents; nor is the title expected to give the details contained in the bill. Gruen v. State Tax Comm’n, 35 Wn.2d 1, 211 P.2d 651 (1949); Cory v. Nethery, 19 Wn.2d 326, 142 P.2d 488 (1943); Sorenson v. Kittitas Reclamation Dist., 70 Wash. 528, 127 Pac. 102 (1912); State ex rel. Zent v. Nichols, 50 Wash. 508, 97 Pac. 728 (1908); State ex rel. Cole v. City of New Whatcom, 3 Wash. 7, 27 Pac. 1020 (1891).
When the words in a title can be given two interpretations, one of which renders the act unconstitutional and the other constitutional, we adopt the constitutional interpretation and sustain the constitutionality of the act. Martin v. Aleinikoff, 63 Wn.2d 842, 389 P.2d 422 (1964); State ex rel. Dawes v. Highway Comm’n, 63 Wn.2d 34, 385 P.2d 376 (1963); Engen v. Arnold, 61 Wn.2d 641, 379 P.2d 990 (1963); Yelle v. Bishop, 55 Wn.2d 286, 347 P.2d 1081 (1959); Hammack v. Monroe Street Lumber Co., 54 Wn.2d 224, 339 P.2d 684 (1959).
The test of the sufficiency of a title is that it must give notice of its object so as reasonably to lead to an inquiry into its contents. Rourke v. Department of Labor & Indus., 41 Wn.2d 310, 249 P.2d 236 (1952); Cory v. Nethery, supra; Sorenson v. Kittitas Reclamation Dist., supra. The title to an act may be general, and all matters incidental or germane thereto may be written into the body of the law. Gruen v. State Tax Comm’n, supra; In re Peterson’s Estate, 182 Wash. 29, 45 P.2d 45 (1935); National Ass’n of Creditors, Inc. v. Brown, 147 Wash. 1, 264 Pac. 1005 (1928), and case cited.
The crucial words in the questioned title are “contractors,” “registration,” and “penalties.” Are these words sufficient notice of the object of the act so as reasonably to lead to further inquiry into the contents of the act? If so, the title meets the test of sufficiency.
Upon reading the title to this act, a contractor engaged in business in the state of Washington would be led to inquire whether his business was within the purview of the regulatory measure. The first section of the act would *492give him the answer. If his business required that he register, he would then reasonably seek further information from the act to determine whether he qualified for a certificate of registration. Section 4, supra, would put him on notice that, in order to qualify and be issued a certificate of registration, he would be required to furnish a surety bond to the state for the payment of the obligations enumerated in § 4. Section 5, supra, would put him on notice that a public liability and property damage insurance policy is required.
Every legislative enactment requiring registration is an exercise of the legislature’s police power, and is, by its nature, regulatory of the subject matter. The word “registration” encompasses all regulatory provisions' which the legislature enacts, in the proper exercise of its police power.
We conclude that the title to chapter 77, Laws of 1963, gave sufficient notice of the object of the act so as reasonably to lead to further inquiry into the contents of the act, and thus meets the test of sufficiency.
Does the act embrace more than one subject?
Since regulation is inherent in every legislative enactment requiring registration, all matters incidental and germane to registration may be written in the body of the law. In the instant case, the legislature, in the proper exercise of its discretion, has required that, as a condition precedent to the issuance of a certificate of registration, the applicant is required to establish his financial responsibility. This requirement, although regulative in nature, is germane to the subject of registration.
We hold that the requirement of establishing financial responsibility does not introduce another subject, and that chapter 77, Laws of 1963, does not embrace more than one subject.
The respondents contend that, although the trial court held the act unconstitutional because of a defective title, the trial court’s judgment can be sustained upon any other constitutional ground within the pleadings and the proof.
Respondents’ pleadings further alleged that the act is unconstitutional because (1) it is violative of the due *493process and equal protection clauses of the federal and state constitutions in that the bond or financial responsibility requirement is unreasonable and confiscatory, the act is discriminatory and creates arbitrary classifications, and requires registration as a condition precedent to maintaining an action predicated upon a construction contract, and (2) that the provisions of the act, taken as a whole, constitute imprisonment for debt in violation of art. 1, § 17, of the state constitution.
Although these constitutional issues were presented to the trial court, the court did not predicate its judgment upon any of these alleged constitutional violations. We must assume that the trial court found them to be without merit.
A legislative enactment requiring the registration of contractors is an exercise of the police power of the state. Clark v. Dwyer, 56 Wn.2d 425, 353 P.2d 941 (1960); Parrott & Co. v. Benson, 114 Wash. 117, 194 Pac. 986 (1921); State v. Seattle Taxicab & Transfer Co., 90 Wash. 416, 156 Pac. 837 (1916); State v. Bowen & Co., 86 Wash. 23, 149 Pac. 330 (1915).
The exercise of police power by the legislature is an attribute of sovereignty. It is an essential element of the power to govern. The only limitation upon the exercise of this sovereign power by a legislative body is that the questioned enactment must reasonably tend to correct some evil or promote some public interest, and that it must not be violative of any positive mandate of the constitution. Clark v. Dwyer, supra, at 432, and case cited.
One who attacks the classification provisions of a legislative enactment has the burden of establishing that the classification is manifestly arbitrary, unreasonable, inequitable, and unjust. State v. Persinger, 62 Wn.2d 362, 368, 382 P.2d 497 (1963), and cases cited. To require the furnishing of a bond to insure compliance with the law is a reasonable exercise of police power. Clark v. Dwyer, supra; State ex rel. Milwaukee Grain Elevator Co. v. Robinson, 186 Wash. 557, 59 P.2d 365 (1936); State v. Seattle Taxicab & Transfer Co., supra; State v. Bowen & Co., supra; Fer*494guson-Hendrix Co. v. Fidelity & Deposit Co. of Maryland, 79 Wash. 528, 140 Pac. 700 (1914); State ex rel. Davis-Smith Co. v. Clausen, 65 Wash. 156, 117 Pac. 1101 (1911).
The wisdom, necessity or expediency of a legislative enactment is not subject to judicial review. Port of Tacoma v. Parosa, 52 Wn.2d 181, 324 P.2d 438 (1958); Bulette v. Bremerton, 34 Wn.2d 834, 210 P.2d 408 (1949); Gazzam v. Building Serv. Employees Int’l Union, Local 262, 29 Wn.2d 488, 188 P.2d 97 (1947); State ex rel. Govan v. Clausen, 108 Wash. 133, 183 Pac. 115 (1919).
The imposition of a fine or imprisonment for violation of a legislative enactment is not imprisonment for debt, but a statutory penalty imposed upon any person who shall knowingly and intentionally violate a lawful mandate of the legislature. Decker v. Decker, 52 Wn.2d 456, 326 P.2d 332 (1958); Austin v. Seattle, 176 Wash. 654, 30 P.2d 646, 93 A.L.R. 203 (1934); State v. Seattle Taxicab & Transfer Co., supra.
Applying the above rules to chapter 77, Laws of 1963, we hold that the standards fixed by the legislature for the registration of contractors and the classifications prescribed by the act do not violate any of the constitutional mandates relied upon by respondents.
The judgment of the trial court is reversed, and the cause remanded with instructions to enter judgment in accordance with the views herein expressed.
Finley, Weaver, Hunter, Hamilton, and Hale, JJ., concur.
Hill, J., concurs in the result.