In Fong Yue Ting v. United States, 149 U.S. 698 (1893), an Act of Congress was involved which required every Chinese alien within one year to procure from the Collector of Internal Revenue a certificate of residence and made it the duty of such alien to produce the certificate on request. Any officer was authorized to arrest a Chinese alien failing to produce the certificate on request and to hold him for deportation. The Act placed on the alien the burden of proving at the deportation hearing his residence and of excusing his failure to procure a certificate. Failure to have in his possession the certificate the law required him to have gave rise to a natural inference of intentional failure to procure it or unlawful residence in the country which precluded his procuring it. In such a situation the shifting to the alien of the burden of explanation imposed no unreasonable hardship upon him.