Unpublished paper, 'Experiments relative to animal temperature, showing that there must be some source of animal heat besides, the combustion of the carbon and the hydrogen contained in the food of animals' by Robert Rigg The subject of these experiments is a labouring man in the employment of the author, living on his ordinary food, and working at his usual employment. Rigg examines the quantity and chemical constituents of the ingesta and egesta of the man during ten days; at the end of which time he had gained one pound in weight. Rigg infers from the results of this experiment that the carbon and hydrogen contained in the food of animals, which enter into combination with the respired oxygen, forming carbonic acid and water, do not generate sufficient heat for the purposes of animal life; and that consequently there must be some other sources of heat in the animal economy, one of which he believes to be the secretion of carbon. Marked on back as 'Archives 12 November 1846 S H C [Samuel Hunter Christie]'. Subject: Physiology Received 27 May 1846. Written by Rigg in Greenford [London]. An abstract of the paper was published in volume 5 of Abstracts of the Papers Printed in the Philosophical Transactions of the Royal Society of London [later Proceedings of the Royal Society] as 'Experiments relative to animal temperature, showing that there must be some source of animal heat besides the combustion of the carbon and the hydrogen contained in the food of animals'. 26 May 1846