The code of 1909 permits the importation of periodicals containing copyright matter authorized by the copyright proprietor, though not manufactured in the United States, but this permissive exception does not extend to composite books; and under the law of 1891 the Treasury Department held that in the case of a book of poems, some of which were copyrighted in the United States, the book could not be imported unless the parts containing copyrighted poems had been printed from type set within the United States. Under this ruling, applied to the present law, foreign-made copies of books containing American copyrighted poems or other articles, must be denied importation, because these copyrighted portions were not type-set, printed and bound in this country. It is possible, however, that under the rule "_de minimis non curat lex_," a court might not justify the prohibition of books incidentally containing in small proportion poems, extracts or other negligible items of American copyright. Thus if an English cyclopaedia contained copyrighted contributions by American authors, such cyclopaedia would be denied admission unless such contributions might be adjudged a negligible proportion of the work. {Sidenote: Rebinding abroad} The prohibition of importation under the manufacturing proviso of copyrighted books not bound in this country, has been construed by the Attorney-General, in an opinion of March 1, 1910 (given in Treas. dec. no. 30414), to refer to original bindings and not to rebindings. "Manifestly a book is produced within the meaning of section 31 when it is printed and bound; and the binding required to be done in the United States is the original binding, the one which enters into the original production of the book. When the manufacture of the book is thus completed it is entitled to all the protection offered by the copyright laws, and it may be exported and thereafter imported at the pleasure of the owner. There is, furthermore, nothing in the act to indicate any intention that a book may be deprived of this protection or right of importation when it has once been acquired. If it shall become necessary or proper that the book be rebound it is not thereby made a new book, but remains the same book, the one that was printed and originally bound in the United States as required by the statute." {Sidenote: Importation of non-copyright translation}