Although normal for most of his childhood, Sprague began losing weight at age 12 after feeling ill after swimming. In 1865, he joined a circussideshow, becoming "the Living Skeleton" or "the Original Thin Man". The next year P. T. Barnum hired Sprague to work at his (newly reopened) American Museum until it burned down in 1868, continuing off and on to tour him throughout the country. By the age of 44, he was 5 feet and 6 inches tall with a weight of only 43 pounds.
^ abcd"Death of 'Living Skeleton'". New York Times. January 7, 1887. Retrieved 2015-03-28. Isaac Sprague, the "living skeleton," died here yesterday. He was born in Bridgeport, Mass., and was quite healthy until his twelfth year, when he caught a cramp while in swimming, fell sick, and lost flesh until he weighed only 46 pounds. Barnum took him all over the United States, Canada, and England. He was married and the father of three robust children.