The first session of the Fortieth Congress adjourned on the 30th day of March, 1867. This bill, + which was passed during that session, was not presented for my approval by the Hon. Edmund G. Ross, of the Senate of the United States, and a member of the Committee on Enrolled Bills, until Monday, the 1st day of April, 1867, two days after the adjournment. It is not believed that the approval of any bill after the adjournment of Congress, whether presented before or after such adjournment, is authorized by the Constitution of the United States, that instrument expressly declaring that no bill shall become a law the return of which may have been prevented by the adjournment of Congress. To concede that under the Constitution the President, after the adjournment of Congress, may, without limitation in respect to time, exercise the power of approval, and thus determine at his discretion whether or not bills shall become laws, might subject the executive and legislative departments of the Government to influences most pernicious to correct legislation and sound public morals, and--with a single exception, occurring during the prevalence of civil war--would be contrary to the established practice of the Government from its inauguration to the present time. This bill will therefore be filed in the office of the Secretary of State without my approval.
* Pocket veto. Was never sent to Congress, but was deposited in the Department of State.
+ "Joint resolution placing certain troops of Missouri on an equal footing with others as to bounties."
Andrew Johnson, Veto Message Online by Gerhard Peters and John T. Woolley, The American Presidency Project https://www.presidency.ucsb.edu/node/203360