It is to be regretted that our representations in regard to the injurious effects, especially upon the revenue of the United States, of the policy of the Mexican Government in exempting from impost duties a large tract of its territory on our borders have not only been fruitless, but that it is even proposed in that country to extend the limits within which the privilege adverted to has hitherto been enjoyed. The expediency of taking into your serious consideration proper measures for countervailing the policy referred to will, it is presumed, engage your earnest attention. It is the obvious interest, especially of neighboring nations, to provide against impunity to those who may have committed high crimes within their borders and who may have sought refuge abroad. For this purpose extradition treaties have been concluded with several of the Central American Republics, and others are in progress. The sense of Congress is desired, as early as may be convenient, upon the proceedings of the commission on claims against Venezuela, as communicated in my messages of March 16, 1869, March 1, 1870, and March 31, 1870. It has not been deemed advisable to distribute any of the money which has been received from that Government until Congress shall have acted on the subject. The massacres of French and Russian residents at Tien-Tsin, under circumstances of great barbarity, was supposed by some to have been premeditated, and to indicate a purpose among the populace to exterminate foreigners in the Chinese Empire. The evidence fails to establish such a supposition, but shows a complicity between the local authorities and the mob. The Government at Peking, however, seems to have been disposed to fulfill its treaty obligations so far as it was able to do so. Unfortunately, the news of the war between the German States and France reached China soon after the massacre. It would appear that the popular mind became possessed with the idea that this contest, extending to Chinese waters, would neutralize the Christian influence and power, and that the time was coming when the superstitious masses might expel all foreigners and restore mandarin influence. Anticipating trouble from this cause, I invited France and North Germany to make an authorized suspension of hostilities in the East (where they were temporarily suspended by act of the commanders), and to act together for the future protection in China of the lives and properties of Americans and Europeans. Since the adjournment of Congress the ratifications of the treaty with Great Britain for abolishing the mixed courts for the suppression of the slave trade have been exchanged. It is believed that the slave trade is now confined to the eastern coast of Africa, whence the slaves are taken to Arabian markets.