Deemer, J.
1 *6442 *643The statute under which the information was filed reads as follows: “If any person shall sell * * any adulterated * * * milk * * * he shall be fined,” etc. Section 4989. Section 4990 reads, “For the purpose of this chapter the addition of water or any other substance or thing, to whole milk or skimmed milk or partly skimmed milk, is hereby declared an adulteration,” etc. There is no question that defendant sold milk to various persons into which he had put and mixed boracie acid. Some of them were notified of the adulteration, *644but others were not. He testifies that he dissolved 5 pounds of the acid in 20 gallons of water, and added 1 pint of the solution to 10 gallons of milk; that he used it as a preservative, and told quite a number of his customers that he was using the solution -for the purpose indicated; that he never attempted to deceive any of his customers regarding the use of the solution; and that its use was necessary “to keep the milk from souring.” He also introduced experts to show that the quantity of boracic acid used tended to prevent decomposition, and would have no deleterious effect on the consumers. For the purpose of the ease, we must assume that the quantity of acid used by the defendant in the milk sold by him had no deleterious effect, but tended to prevent decomposition and the development of germs. The experts also testified, however, that the addition of an excessive amount of boracic acid would have a deleterious effect, in that it would retard the formation of gastric juice in the stomach. The learned district judge filed an opinion in which he held, in effect, that the statute, construed literally, was unconstitutional, and that the evident intent of the legislature was to prohibit .sales of anything that would operate as a fraud upon the buyer or prove deleterious to his health, and that, as the defendant was guilty of no fraud and the adulteration was harmless, he had not violated the law. These propositions are insisted upon by the appellee, and further contention is -.made that if the statute is not so construed it is unconstitutional, for various reasons, that will he referred to' during the course of the opinion. It seems to us that the construction placed on the statute hy the trial court is a strained and unnatural one. The language of the enactment is plain, and in view of previous legislation there is no doubt that the act should have a literal interpretation. That the legislature so intended is not open to serious debate. So construed, are the acts in question constitutional ?
*6453 Section 4990 is said to be void because it invades tbe judicial province, in that it is not permissible for tbe legislature to make certain evidence conclusive of a question that may be submitted to judicial determination. No doubt, tbe legislature cannot indirectly dispose of a cause by prescribing conclusive rules of evidence, and it has no power to direct tbe judiciary in tbe interpretation of existing statutes. Groesbeck v. Seeley, 13 Mich. 329; Johns v. State, 55 Md. 362; Reiser v. Association, 39 Pa. St. 137; Salters v. Tobias, 3 Paige, 338. But it does have power to prescribe legal definitions of its own language, and, when an act passed by it embodies a definition, it is binding on tbe courts. Smith v. State, 28 Ind. 321; Jones v. Surprise, 64 N. H. 243 (9 Atl. Rep. 384) ; Byrd v. State, 57 Miss. 243 (34 Am. Rep. 440) ; Herold v. State, 21 Neb. 50 (31 N. W. Rep. 258) ; Clay v. Railroad Co., 84 Ga. 345 (10 S. E. Rep. 967) ; People v. Board of Supervisors of New York City, 16 N. Y. 424. Even declaratory statutes are entitled to respectful consideration by tbe courts, although not always binding. Cooley Statutory Crimes (2d ed.) section 91; People v. Board of Supervisors of New York City, supra; Lambertson v. Hogan, 2 Pa. St. 25. The definition given by the legislature in section 4990 of the Code as to the term “adulteration” is valid and-binding. Such legislation does not trench on the powers of the judiciary, and is not invalid for the reason suggested.
4 But it is said that the legislature had no power to forbid the sale, without deceit or fraud, of a harmless and wholesome article of food. This may be true, as a general proposition; but it is also true that in virtue of the police power it may pass such laws as are, or may reasonably appear to be, necessary for the health, comfort, and safety of the people. No clear and comprehensive definition of the police power has ever been given, and it is doubtful if one can be framed that will be accurate and cover every_ con*646ceivable case that may arise. It is much easier to determine whether the particular case comes within the scope of the power, than to give a definition that will be applicable to all cases. In Railroad Co. v. Husen, 95 U. S. 465 (24 L. Ed. 527), it is said, “The police power of a state extends to the protection of the lives, limbs, health, comfort, and quiet of all persons, and to the protection of all property within the state, and hence to the making of all regulations promotive of domestic order, morals, health, and safety.” The power belongs to the several states, and not to the federal government, save in exceptional cases; and, so-long as the legislature docs not pass the limits prescribed by the federal or state constitutions, courts have no authority to interfere on the ground that the acts in question violate natural principles of right and justice. Ordinarily the legislature determines when the public welfare and safety demand its exercise; and, as a general rule, courts have nothing to do with the policy, wisdom, or necessity of the enactment. Of course, the state cannot, by arbitrarily assuming that a commodity is injurious to the health or comfort of the people, impair individual rights guaranteed by the constitution. The police power of the state, like every other, is subject-to the constitution, and cannot be • used as a cloak under which to disregard constitutional rights or restrictions. Railroad Co. v. Husen, supra; In re Jacobs, 98 N. Y. 98. The question is, of necessity, primarily with the legislature, and its decision should not be lightly disregarded by the courts. Courts will not interfere, as a rule, unless there is a plain excess or usurpation of power, and in case of doubt it should be solved in favor of the power of the legislature to make the enactment. It was an indictable offense at common law to mix unwholesome ingredients, such as alum, in bread, or to mix unwholesome substances in anything intended for the food of man. There is an ancient statute (Statutes 51 Henry III.) prohibiting the sale of corrupted wine, contagious or unwholesome flesh, or flesh *647that is bought of a Jew. 4 Blackstone Commentaries 162. In Rex v. Dixon, 3 Maule & S. 11, defendant was indicted for furnishing bread not fit for food. It appeared that the loaves were strongly impregnated with alum, and that large pieces of crude alum were found in them. Defendant’s motion for a new trial, filed after a verdict of guilty, was overruled ; the court saying that “alum being perilous to health, in the form used, it is immaterial that if used in certain quantities it was not noxious, but wholesome.” Statutes enacted to secure the sale of pure food and to prevent adulteration are quite common in this country, and have ever been referred to the police power. See English sale of food and drugs act of 1875 (chapter 63) ; Laws Tenn. 1859-60, chapter 81, section 4; Revised Statutes Mass, chapter 131, section 1. They are enacted to prevent fraud and to conserve the public health, and as such are a valid exercise of the police power. State v. Campbell, 64 N. H. 492 (13 Atl. Rep. 585; People v. Arensburg, 105 N. Y. 123 (11 N. E. Rep. 277); Butler v. Chambers, 36 Minn. 69 (30 N. W. Rep. 308; Waterbury v. Newton, 50 N. J. Law, 534 (14 Atl. Rep. 604) ; Powell v. Pennsylvania, 127 U. S. 679 (8 Sup. Ct. Rep. 992, 1257, 32 L. Ed. 253); Com. v. Waite, 11 Allen, 264 (87 Am. Dec. 711) ; State v. Smythe, 14 R. I. 100 (51 Am. Dec. 343) ; People v. Cipperly, 101 N. Y. 634 (4 N. E. Rep. 107); Com. v. Gordon, 159 Mass. 8 (33 N. E. Rep. 709) ; Com. v. Schaffner, 146 Mass. 512 (16 N. E. Rep. 280).
*6495 *647That the sale of milk to which water and boracic acid have been added may amount to a fraud upon the purchaser is evident. He has the right to assume that the milk he buys is unadulterated, and that it will go through the natural process of oxidation and decomposition. He may wish to use ■sour milk for culinary purposes, and has the right to assume that nothing has been added to prevent chemical change. •Counsel for appellee responds to this thought by saying that *648defendant notified all persons to whom lie sold that boracie acid had been added, and that no one of the witnesses for the state was deceived. The record does not bear them out in this contention, but, even if it did, we would have no help therefrom in solving the constitutional question involved. It may bo conceded that the milk sold by defendant was not harmful to the health of those who used it; but it is certainly dangerous to the public to permit milkmen and those dealing in milk to adulterate it in such manner as to change its constit-uent properties. The statute does not deprive the defendant of his property, but it does impose upon him the duty of so using it that no injury will result to others, most likely to be affected by a disregard on his part of the reasonable health regulations that it enacts. Almost every police regulation affects, to a greater or less extent, some property right; but these rights are subject to such reasonable limitations in their enjoyment as will prevent them from being injurious, and to' such reasonable regulations as the legislature, under the constitution, may deem necessary and expedient. In the Schaffer Case, from Massachusetts, and the Campbell Case, from New Hampshire, it is expressly held to be immaterial whether the foreign matter is or is not injurious to health. The court in the latter case said that, “if the legislature has power to fix a standard, it must judge whether of not milk below that standard is unwholesome;” and in the former it was held that the addition of pure water to milk was an adulteration punishable under the statute. In Com. v. Gordon, supra, it is expressly held that the addition of boracic acid to cream is an offense under the statute of the state of Massachusetts. See, also, Com. v. Wetherbee, 153 Mass. 159 (26 N. E. Rep. 414). In Com. v. Waite, 11 Allen, 264 (87 Am. Dec. 711), the exact question made by defendant in this case was decided, the court using the following language: “It is innocent and lawful to sell pure milk, and it is innocent and^ lawful to sell pure water; and the argument is that the legisr*649lature has no power to make the sale of milk and water when mixed a penal offense, unless it be done- with a fraudulent, intent. But it is notorious that the sale of milk adulterated with water is extensively practiced with fraudulent intent. It is for the legislature to judge what reasonable laws ought to be enacted to protect the people against this fraud, and to-adapt the protection to the nature of the case. They have-seen fit to require that every man who sells milk shall take the risk of selling a pure article. No man is obliged to go into-the business, and by using proper precautions any dealer can ascertain whether the milk he offers for sale has been watered. The court can see no ground for pronouncing the law unreasonable, and has no authority to judge as to its expediency.” It is not enough to show that defendant did not intend to defraud, or that the milk he' sold was wholesome. If' that were true, almost any law intended to protect the public health and safety might be overthrown. It is enough that' adulteration such as prescribed by the statute may defraud or prove deleterious to the public health or comfort. The-legislature may well determine that the adulteration of milk' tends to facilitate vicious practices, and that it ought to be-prohibited. To defeat the act prohibiting such conduct, it is. not enough .to show that in the particular ease the-article sold was innocuous. Criminal intent is not. an essential element of the offense described in the-statute, and need not be shown in order to justify a conviction. Com. v. Smith, 103 Mass. 444; Com. v. Farren, 9 Allen, 489; Com. v. Nichols, 10 Allen, 199; People v. Kibler, 106 N. Y. 321 (12 N. E. Rep. 795); State v. Smith, 10 R. I. 258. If the statute required knowledge or intent, of course these matters should be shown. These propositions are a sufficient answer to the opinion of the trial court, holding that an intent to defraud is necessary.
*6506 *649Appellee further contends that the statute in question is in violation of the fourteenth amendment to the federal con*650stitution. Such, contention is not sound, for it is fundaamental that this amendment does not impose any restraints on the exercise of the police power of the state for the protection of the safety, health, or ■morals of the community. Barbler v. Connoly, 113 U. S. 27 (5 Sup. Ct. Rep. 371, 28 L. Ed. 923) ; Kidd v. Pearson, 128 U. S. 1 (9 Sup. Ct. Rep. 6, 32 L. Ed. 346) ; In re Rahrer, 140 U. S. 545 (11 Sup. Ct Rep. 865, 35 L. Ed. 572) ; People v. King, 110 N. Y. 418 (18 N. E. Rep. 245). The conclusión of the learned trial judge was made to depend almost wholly on the facts developed by the evidence. If the jury had found the milk as adulterated, — unwholesome,—we have no doubt that the trial court would have sustained the convictions. That the constitutionality of a statute ought not to' be made to depend on the finding of a jury on the facts of .a case is manifest. If the plain provisions of the constitution have been violated, or if the act cannot be said to be a proper •exercise of the police power, in view of'facts of which judicial notice may be taken, then the duty of declaring the act invalid is clear. But, in the absence of such finding, the act should stand. Ordinarily it cannot, we think, be a question •of fact for a jury. See People v. Cipperly, supra; People v. Smith, 108 Mich. 527 (66 N. W. Rep. 382). People v. Marx, 99 N. Y. 377 (2 N. E. Rep. 29), is relied on by appellee. That case involved the right to sell oleomargarine, and not the question of adulteration. That it is not in conflict ■with anything we have announced clearly appears from the Cipperly Case, in 101 N. Y. 634 (4 N. E. Rep. 107). See, also, People v. Arensburg, 103 N. Y. 388 (8 N. E. Rep. 736). Schollenberger v. Pennsylvania, 171 U. S. 1 (18 Sup. Ct. Rep. 757, 43 L. Ed. 49), involved the commerce clause ■ of the federal constitution; and it was held that the legislature could not, under the guise of the police power, absolutely prohibit the sale of articles which are the subjects of inter■•state commerce. It does not overrule Powell v. Pennsyl*651vania, 127 U. S. 678 (8 Sup. Ct. Rep. 992, 1257, 32 L. Ed. 253), or Plumley v. Massachusetts, 155 U. S. 461 (15 Sup. Ct. Rep. 154, 39 L. Ed. 223), and, as those cases sustain our Bolding, we may well rest thereon.
Lastly, it is said that section 4990 of the Code is void because the subject is not expressed in the title. The act is found in the Code of 1897. Whether or not it existed prior to that time is immaterial to our present inquiry. Some claim is made that the title of the act adopting the Code, and particularly that part of it under consideration, is insufficient. Our attention has not been called to any defects in the enactment of the Code, either as a whole, or by titles and chapters; and in the absence of such a showing, and of the most cogent arguments in support of the claim, we are not justified in holding that either the Code or any section or chapter thereof is void because of the constitutional provision defining what •shall be embraced in the .title of an act. The title to the •original act was sufficiently specific. State v. Forkner, 94 Iowa, 1; State v. Snow, 81 Iowa, 642; Christie v. Investment Co., 82 Iowa, 360.
We have covered all points made in argument, and reach the conclusion that the trial court was in error in his conclu■sions of law; and we therefore reverse the same, to the end that the proper rule may be established for such cases.— Reversed.