the officer executing the warrant.[26] Private papers of
no pecuniary value, in which the sole interest of the Federal Government
is their value as evidence against the owner in a contemplated criminal
prosecution, may not be taken from the owner's house or office under a
search warrant.[27]

Records, Reports and Subpoenas

Since the common law did not countenance compulsory self incrimination,
many years passed before the Supreme Court was called upon to interpret
the constitutional provisions bearing upon the privilege against such
testimonial compulsion. Not until Boyd _v._ United States[28] did it
have to meet the issue; there, pursuant to an act of Congress, a court
had issued an order in a proceeding for the forfeiture of goods for
fraudulent nonpayment of customs duties, requiring the claimant to
produce in court his invoices covering the goods, on pain of having the
allegation taken as confessed against him. The order and the statute
which authorized it were held unconstitutional in a notable opinion by
Justice Bradley, as follows: "Breaking into a house and opening boxes
and drawers are circumstances of aggravation; but any forcible and
compulsory extortion of a man's own testimony or of his private papers
to be used as evidence to convict him of crime or to forfeit his goods,
is [forbidden] * * * In this regard the Fourth and Fifth Amendments run
almost into each other."[29] Thus the case established three
propositions of far-reaching significance: (1) that a compulsory
production of the private papers of the owner in such a suit was a
search and seizure within the meaning of the Fourth Amendment;[30] (2)
that in substance such seizure compelled him to be a witness against
himself in violation of Amendment V,[31] and (3) that, because it was a
violation of the Fifth Amendment, it was also an _unreasonable_ search
and seizure under the Fourth.[32]

Only natural persons can resist the subpoena of private papers on the
ground of self incrimination.[33] Even an individual cannot refuse to
produce records which are in his custody on the plea that they might
incriminate the owner or himself where the documents belong to a
corporation,[34] or to a labor union.[35] A bankrupt can be compelled to
turn over records which are part of his estate.[36] Papers already in
the custody of a United States court in consequence of their having been
used by the owner himself as evidence on another proceeding may be used
befor