commission of an unlawful act is responsible for unintended results due to his ignorance of fact does not apply where the act is merely malum prohibitum. Thus it has been held that a man who drives over another is not guilty of criminal assault and battery merely because he was driving at a speed prohibited by an ordinance. 143

(d) Mere Civil. Wrongs.-Nor does the principle apply where the act was a mere civil wrong. Thus, a man who wrongfully threw another's package into the sea, though guilty of a civil trespass, was held not guilty of manslaughter because he unintentionally

143 Com. v. Adams, 114 Mass. 323, 19 Am. Rep. 362, Beale's Cas. 204; 1 Hale, P. C. 39; Fost. C. L. 259.

"It is true that one in pursuit of an unlawful act may sometimes be punished for another act, done without design and by mistake, if the act done was one for which he could have been punished if done willfully. But the act, to be unlawful in this sense, must be an act bad in itself, and done with an evil intent; and the law has always made this distinction: That if the act the party was doing was merely malum prohibitum, he should not be punishable for the act arising from misfortune or mistake; but, if malum in se, it is otherwise." Com. v. Adams, supra.

killed a person who was bathing in the sea.144 72. Negligence.

Ignorance of fact is no defense, as a general rule, if the accused could have known the facts if he had exercised reasonable care and diligence.145 Thus, a person who negligently throws a board from a building into the street, and kills a person on the street, cannot escape responsibility for the homicide on the ground that he did not know, any person was passing along the street.146 The same is true of a man who causes another's death by negligent use of a gun which he believes to be unloaded,147 or by the use of dangerous drugs which he does not understand, etc.148

The same principle applies to statutory offenses, on a prosecution for which non-negligent ignorance of fact would be held an excuse. Thus, in those states in which it is held that a statute punishing the sale of intoxicating liquors to minors or drunkards

144 Reg. v. Franklin, 15 Cox, C. C. 163, Beale's Cas. 203.

145 Dotson v. State, 62 Ala. 141, 34 Am. Rep. 2; Swigart v. State, 99 Ind. 111.

does not apply where a person sells to a minor or drunkard in the bona fide and reasonable belief that he is over twenty-one years of age, or not a drunkard,149 it has been held that such belief is no defense if there is negligence, as where the belief is based merely on the statement of the party himself.15 150 The same is true under a statute punishing bigamy.151

III. IGNORANCE OR MISTAKE OF LAW. 73. In General.-Every person is conclusively presumed to know the law, and, on a prosecution for a crime, ignorance or mistake of law is no excuse. The rule does not apply, however, where, by reason of mistake as to one's legal rights, there was an absence of a specific criminal intent which is essential to the crime charged.

There is no principle of the criminal law that is better settled than this. The maxim is, "ignorantia legis neminem excusat." Every man is conclusively presumed to know the law, and on a prosecution for a crime,

149 Ante, § 70 (b).

150 Swigart v. State, 99 Ind. 111; Goetz v. State, 41 Ind. 162; Crabtree v. State, 30 Ohio St. 382.

151 A man who marries a second time during his first wife's life, without reasonable grounds to believe her to be dead, is liable to indictment for bigamy Dotson v. State, 62 Ala. 141, 34 Am. Rep. 2; Reynolds v. State (Neb.) 78 N. W. 483.

whether common law or statutory, he cannot escape responsibility by showing that he was ignorant or mistaken as to the law,152 even though he may have acted in the most perfect good faith, and under advice of counsel.153

152 1 Coke, 177; Broom, Leg. Max. 253; 1 Hale P. C. 42; Rex v. Bailey, Russ. & R. 1, Beale's Cas. 280; The Barronet's Case, 1 El. & Bl. 1; Rex v. Esop, 7 Car. & P. 456, Beale's Cas. 282; Reynolds v. U. S., 98 U. S. 145, Beale's Cas. 179; State v. Goodenow, 65 Me. 30, Beale's Cas. 309; Jellico Coal Min. Co. v. Com., 96 Ky. 373; Halsted v. State, 41 N. J. Law, 552, 32 Am. Rep. 247; Lancaster v. State, 3 Cold. (Tenn.) 340, 91 Am. Dec. 288; State v. Welch, 73 Mo. 284, 39 Am. Rep. 515. And see the other cases cited in the notes following.

Everyone

"Ignorantia legis neminem excusat. competent to act for himself is presumed to know the law. No one is allowed to excuse himself by pleading ignorance. Courts are compelled to act upon this rule, as well in criminal as civil matters. It lies at the foundation of the administration of justice. And there is no telling to what extent, if admissible, the plea of ignorance would be carried, or the degree of embarrassment that would be introduced into every trial by conflicting evidence upon the question of ignorance.

To allow ignorance as an excuse would be to offer a reward to the ignorant." Per Pearson, J., in State v. Boyett, 10 Ired. (N. C.) 336, 343.

153 Halsted v. State, 41 N. J. Law, 552, 32 Am. Rep. 247. And see State v. Goodenow, 65 Me. 30,

Application of the Rule. Thus, on a prosecution for bigamy in violation of an act of congress, it was held that the accused could not escape responsibility by showing that he was a Mormon, and that he married the second wife in accordance with his religious belief, and thinking that he had a right to do so. His belief that the law did not apply to him, or that it was unconstitutional, was nothing more than ignorance or mistake of the law.154 The principle also applies in a prosecution for bigamy or adultery, in which the accused sets up in defense that he believed that a void decree of divorce obtained by him or the other party was valid,155 or that by reason of any other mistake as to the law he believed he had a

Beale's Cas. 309; State v. Hughes, 58 Iowa, 165; People v. Weed, 29 Hun (N. Y.) 628.

154 Reynolds v. U. S., 98 U. S. 145, Beale's Cas. 179.

155 State v. Goodenow, 65 Me. 30, Beale's Cas. 309; State v. Hughes, 58 Iowa, 165; State v. Whitcomb, 52 Iowa, 85, 35 Am. Rep. 258; Russell v. State, 66 Ark. 185; Reynolds v. State (Neb.) 78 N. W. 483. And see Davis v. Com., 13 Bush. (Ky.) 318; State v. Armington, 25 Minn. 29. Compare Squire v. State, 46 Ind. 459.