8 GRAHAM LUSK 



VIII. "Mutton easily digests and perspires; or it will waste in a night a 

 third part of a Pound more than any other usual Food." 



XXIII. "Pork and Mushrooms are bad both because they do not Perspire 

 themselves and because they hinder the Perspiration of other things eat along 

 with them." 



LIX. "If a Supper of eight Pounds corrupts' in the Stomach, the next Day 

 the Body will be lighter than after a Supper of three Pound which does not do 

 so." 



These aphorisms summarized signify that a well appreciated meat, 

 such as mutton, increases the perspiration, whereas pork, which very 

 likely then as now was an unpopular food in Italy, causes "corruption" 

 and diarrhea and hence no increase in perspiration. 



This kind of investigation was continued by Dodart (died 1707) in 

 France, who devoted thirty-three years of exhaustive labor to the subject. 



Then followed the first discovery of carbonic acid gas by Van Hel- 

 mont in the seventeenth century. 



Van Helmont (1577-1644), a member of the ancient princely family 

 of the Counts of Merode of Belgium, was one who consecrated his life 

 to his laboratory. He discovered that when charcoal burned or wine 

 fermented a gas was produced which was as invisible as respired air; 

 that it is sometimes emitted from the bowels of the earth in mines or 

 at the Grotto del Carno (near Naples so called because if a man 

 enters it accompanied by a dog, the man lives but the dog dies, since 

 carbon dioxid gas evolved is heavier than air and remains near the 

 ground) ; that it is present in the waters of Spa and is evolved when 

 vinegar is poured on chalk. This gaz sylvestre ("wood gas") does not 

 maintain a flame nor life of animals. It promptly results in their 

 asphyxiation and death. 



Jean Rey, born about the end of the sixteenth century, died 1645, a 

 physician of Perigord, found in 1630 that tin and lead increased in 

 weight when calcined, but the significance of these facts was neglected 

 in the subsequent enthusiasm over phlogiston. Key's work, "Essays sur 

 la recherche de la cause pour laquelle 1'estain et le plomb augmentent de 

 poids quand on les calcine," 1630, was reprinted after Lavoisier's dis- 

 coveries in 1777. 



Nicholas Lefevre (died 1674), in his "Traite de Chimie," published 

 about 1660, says, "In the act of respiration the air does not confine 

 itself to refreshing the lungs, but by means of the 'universal spirit' it 

 reacts upon the blood, refining it and volatilizing all its superfluities." 

 A hundred years later Haller had about the same viewpoint. Lefevre 

 was one of the founders of the Academie des Sciences and was physician- 

 in-chief to Louis XIV. 



Robert Boyle (1621-1679) in 1660 showed tbat the flame of a candle 

 or the life of an animal was extinguished after placing them in an air 

 pump. Between 1668 and 1678 he made numerous experiments with 



