it is for the Government, and not for its courts, to
adopt the principle of retorsion, if deemed under any circumstances
desirable or necessary." At the same sitting of the Court, an action in
a United States circuit court on a Canadian judgment was sustained on
the same ground of reciprocity. Ritchie _v._ McMullen, 159 U.S. 235
(1895). _See also_ Ingenohl _v._ Olsen, 273 U.S. 541 (1927), where a
decision of the Supreme Court of the Philippine Islands was reversed for
refusal to enforce a judgment of the Supreme Court of the British colony
of Hongkong, which was rendered "after a fair trial by a court having
jurisdiction of the parties." In 1897 Foreign Relations of the United
States 7-8, will be found a three-cornered correspondence between the
State Department, the Austro-Hungarian Legation, and the Governor of
Pennsylvania, in which the last named asserts that "under the laws of
Pennsylvania the judgment of a court of competent jurisdiction in
Croatia would be respected to the extent of permitting such judgment to
be sued upon in the courts of Pennsylvania." Stowell, _op. cit. supra_
note I, at 254-255. Another instance of international cooperation in the
judicial field is furnished by letters rogatory. "When letters rogatory
are addressed from any court of a foreign country to any district court
of the United States, a commissioner of such district court designated
by said court to make the examination of the witnesses mentioned in said
letters, shall have power to compel the witnesses to appear and depose
in the same manner as witnesses may be compelled to appear and testify
in courts," 28 U.S.C.A., _supra_ note II, Sec. 653. Some of the States
have similar laws. _See_ 2 Moore, Digest of International Law (1906)
108-109.

[132] David K. Watson, The Constitution of the United States, vol. II,
1206 (1910).

[133] The Federalist No. 42.

[134] 16 Wall. 36 (1873).

[135] Ibid. 75.

[136] Scott _v._ Sandford, 19 How. 393 (1857).

[137] Ibid. 518, 527-529.

[138] 153 U.S. 684, 687 (1894).

[139] 135 U.S. 492 (1890).

[140] Slaughter-House Case, 15 Fed. Cas. No. 8408 (1870); Chambers _v._
Baltimore & O.R. Co., 207 U.S. 142 (1907); Whitfield _v._ Ohio, 297 U.S.
431 (1936).

[141] 16 Wall. 36 (1873).

[142] Ibid. 77.

[143] Bradwell _v._ Illinois, 16 Wall. 130, 138 (1873). _See also_ Cole
_v._ Cunningham, 133 U.S. 107 (1890).

[144] Blake _v._ McClung, 172 U.S. 239, 246 (1898); Travis _v._ Yale &
Towne M