<P> Lavoisier employed the new nomenclature in his Traité élémentaire de chimie (Elementary Treatise on Chemistry), published in 1789 . This work represents the synthesis of Lavoisier's contribution to chemistry and can be considered the first modern textbook on the subject . The core of the work was the oxygen theory, and the work became a most effective vehicle for the transmission of the new doctrines . It presented a unified view of new theories of chemistry, contained a clear statement of the law of conservation of mass, and denied the existence of phlogiston . This text clarified the concept of an element as a substance that could not be broken down by any known method of chemical analysis, and presented Lavoisier's theory of the formation of chemical compounds from elements . It remains a classic in the history of science . While many leading chemists of the time refused to accept Lavoisier's new ideas, demand for Traité élémentaire as a textbook in Edinburgh was sufficient to merit translation into English within about a year of its French publication . In any event, the Traité élémentaire was sufficiently sound to convince the next generation . </P> <P> The relationship between combustion and respiration had long been recognized from the essential role which air played in both processes . Lavoisier was almost obliged, therefore, to extend his new theory of combustion to include the area of respiration physiology . His first memoirs on this topic were read to the Academy of Sciences in 1777, but his most significant contribution to this field was made in the winter of 1782 / 1783 in association with Laplace . The result of this work was published in a memoir, "On Heat ." Lavoisier and Laplace designed an ice calorimeter apparatus for measuring the amount of heat given off during combustion or respiration . The outer shell of the calorimeter was packed with snow, which melted to maintain a constant temperature of 0 ° C around an inner shell filled with ice . By measuring the quantity of carbon dioxide and heat produced by confining a live guinea pig in this apparatus, and by comparing the amount of heat produced when sufficient carbon was burned in the ice calorimeter to produce the same amount of carbon dioxide as that which the guinea pig exhaled, they concluded that respiration was in fact a slow combustion process . Lavoisier stated, "la respiration est donc une combustion," that is, respiratory gas exchange is a combustion, like that of a candle burning . </P> <P> This continuous slow combustion, which they supposed took place in the lungs, enabled the living animal to maintain its body temperature above that of its surroundings, thus accounting for the puzzling phenomenon of animal heat . Lavoisier continued these respiration experiments in 1789--1790 in cooperation with Armand Seguin . They designed an ambitious set of experiments to study the whole process of body metabolism and respiration using Seguin as a human guinea pig in the experiments . Their work was only partially completed and published because of the disruption of the Revolution; but Lavoisier's pioneering work in this field served to inspire similar research on physiological processes for generations to come . </P> <Table> <Tr> <Td> </Td> <Td> This section needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (May 2018) (Learn how and when to remove this template message) </Td> </Tr> </Table>

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