Again, the same author, writing on the subject of knowledge, as necessary to establish the intent, says:  “It is absolutely necessary to constitute guilt, as in indictments for uttering forged tokens, or other attempts to defraud, or for receiving stolen goods, and offences of a similar description.” (1 Crim.  Prac.  Sec.504.)

In regard to the offence of obtaining property by false pretenses, the author says:  “The indictment must allege that the defendant knew the pretenses to be false. This is necessary upon the general principles of the law, in order to show an offence, even though the statute does not contain the word ‘knowingly.’” (2 Id.  Sec.172.)

As to a presumed knowledge of the law, where the fact involves a question of law, the same author says:  “The general doctrine laid down in the foregoing sections,” (i.e. that every man is presumed to know the law, and that ignorance of the law does not excuse,) “is plain in itself and plain in its application.  Still there are cases, the precise nature and extent of which are not so obvious, wherein ignorance of the law constitutes, in a sort of indirect way, not in itself a defence, but a foundation on which another defence rests.  Thus, if the guilt or innocence of a prisoner, depends on the fact to be found by the jury, of his having been or not, when he did the act, in some precise mental condition, which mental condition is the gist of the offence, the jury in determining this question of mental condition, may take into consideration his ignorance or misinformation in a matter of law.  For example, to constitute larceny, there must be an intent to steal, which involves the knowledge that the property taken does not belong to the taker; yet, if all the facts concerning the title are known to the accused, and so the question is one merely of law whether the property is his or not, still he may show, and the showing will be a defence to him against the criminal proceeding, that he honestly believed it his through a misapprehension of the law.”

          (1 Cr.  Law, Sec.297.)

The conclusions of the writer here, are correct, but in a part of the statement the learned author has thrown some obscurity over his own principles.  The doctrines elsewhere enunciated by him, show with great clearness, that in such cases the state of the mind constitutes the essence of the offence, and if the state of the mind which the law condemns does not exist, in connection with the act, there is no offence.  It is immaterial whether its non-existence be owing to ignorance of law or ignorance of fact, in either case the fact which the law condemns, the criminal intent, is wanting.  It is not, therefore, in an “indirect way,” that ignorance of the law in such cases constitutes a defence, but in the most direct way possible.  It is not a fact which jurors “may take into consideration,” or not, at their pleasure, but which they must take into consideration, because, in case the ignorance exists, no matter from what cause, the offence which the statute describes is not committed.  In such case, ignorance of the law is not interposed as a shield to one committing a criminal act, but merely to show, as it does show, that no criminal act has been committed.