{Sidenote: Test of piracy} "The true test of piracy," said Judge Shipman in the U. S. Circuit Court in 1875, in Banks _v._ McDivitt, is "whether the defendant has in fact used the plan, arrangements and illustrations as the model of his own book, with colorable alterations and variations, or whether his work is the result of his own labor, skill and use of common materials and common sources." Judge Story said in 1841, in Folsom _v._ Marsh: "If so much is taken that the value of the original is sensibly diminished, or the labours of the original author are substantially, to an injurious extent, appropriated by another, that is sufficient in point of law to constitute a piracy _pro tanto_. The entirety of the copyright is the property of the author and it is no defence that another person has appropriated a part and not the whole of any property." {Sidenote: Infringement in specific meaning} Infringement is commonly taken to mean specific invasion of the author's rights rather than wholesale piracy; and the question of what is infringement or "literary larceny" is more often a question of the interpretation of the facts than the construction of the statute. The legal cases arising under infringement constitute a very large proportion of copyright litigation, demanding as they do judicial determination as to the acts complained of in each particular case. It is therefore impossible in this volume to give citations or references for the hundreds of cases recorded in the law reports or in the various works on copyright, but it may be noted that the foot-note citations in MacGillivray's "Law of copyright" cover a very large number of American as well as English cases. No treatise on copyright can apply, however, in advance, the general principles of copyright to the infinite variety of possible cases; and only generalizations and a few illustrative cases can here be given. {Sidenote: Questions of fact and intent}