32 GRAHAM LUSK 



with the venous blood of the system in the pulmonary vessels. As no light 

 was liberated in Experiment XVII there cannot be even a partial decompo- 

 sition of phosoxygen in respiration. 



Davy's interpretations are far from clear, as will be seen in the 

 following paragraph: "Respiration then is a chemical process, the com- 

 bination of phosoxygen with the venous blood of the lungs and liberation 

 of carbonic acid and aqueous gas from it. From the combination and 

 decomposition arises an increase of repulsive motion which, combined 

 with that produced by the other chemical processes taking place in the 

 system and that generated by the reciprocal action of the solids and 

 fluids, is the cause of animal heat; a heat which the other systems have 

 supposed to arise chiefly from the decomposition of phosoxygen (oxygen 

 and caloric)." 



About the same time that Davy was experimenting in England Spal- 

 lanzani in Italy was inquiring into the validity of Lavoisier's ideas. 



Spallanzani (1729-1799). The experiments of Spallanzani were 

 published in 1804 after his death. His biographer states: "When the 

 Empress Maria Theresa had reestablished the University of Pavia on a 

 more extensive plan she wished to render it at once celebrated by the 

 attainments of its professors; she empowered Count Firmian to invite 

 Spallanzani to give lectures on natural history." 



Spallanzani says that oxygen is transported by the blood to the heart 

 and is necessary for the heart beat, but he is not convinced that oxygen is 

 necessary for the production of carbonic acid. He put snails into two 

 tubes filled, respectively, with atmospheric air and with nitrogen. "On 

 removing them from the tubes at the end of twelve hours I found the 

 animals still alive ; I examined the two aeriform fluids and was astonished 

 to discover that the quantity of carbonic acid' gas was greater in the 

 azotic gas (nitrogen) than in the common air." He obtained the same 

 result when he used hydrogen gas and says, "I shall only conclude from 

 these experiments that it is clearly proved that the carbonic acid gas 

 produced by the living and dead snails in common air resulted not from 

 atmospheric oxygen, since an equal or even a greater quantity of it was 

 obtained in azotic and hydrogen gas." 



This is very nearly the same as Davy's conclusion. Of his method 

 of work Spallanzani says : "Being engaged in similar experiments, it was 

 natural for me to attend to this part of the subject uninfluenced by the 

 opinion of those celebrated men, in order that I might observe only 

 nature herself. This is at least the mode I have always pursued, when 

 it was possible, with respect to the most universally received opinions, 

 however respectable the quarter whence they proceeded; I have always 

 myself examined the facts on. which they were built." 



William F. Edwards (1776-1842) confirmed the work of Spallanzani, 

 finding that frogs when placed in hydrogen gas eliminated in a few hours a 



