1^8 The MitchilUan Theory of Fever 



water — with azote, the volatile alkali (ammonia), ufed as a 

 medicine. 



Carbonic acid gas cannot poffefs a contagious quality, for 

 it is continually generating where its effe&s would be moft 

 hurtful — in the lungs, from whence it is conftantly emitted 

 by expiration. We fwallow it in great quantities in beer 

 and other fermented liquors; and, combined with hydrogen 

 gas, it may, as has been proved by the Englifh pneumatic 

 phyficians, be taken in large dofes as a remedy for different 

 difeafes. 



Azotic gas forms nearly two thirds of the common at- 

 mofphere wc breathe : its bafe united to other fubftances 

 compofes a great portion of our food. Oxygen gas forms the 

 other third— without it we cannot live. 



Such gafes therefore may be mixed with, each other, and 

 yet not be the caufe of contagion. Where then is it to be 

 fouo-ht ? Tn fome chemical union between two or more of 



a 



them, or their bafes, effected, by the operation of fome caufe, 

 during their feparation from the organifed body of which 

 they formed a part, by the procefs of putrefaction. 



Permanently-elaftic fluids owe their gafeous form to a 

 chemical union of caloric with their refpeclive bafes. When 

 this union is once effected, two gafes may be mixed or 

 blended together, as oil with water, or wheat with barley; but 

 no chemical union can be effected between them, the at- 

 traction of the bafe of each for caloric being ftronger than 

 that of the gafes for each other. When the affinity of their 

 bafes for each other is ftronger than for caloric, a chemical 

 union of the b.de^ may take place ; but in that cafe the ca- 

 loric is fet at liberty, and the product, inftead of being ga- 

 feous, is concrete, as when ammoniacal gas is prefented to 

 carbonic acid gas. 



But if the bafes act on each other before either be fatu- 

 rated with caloric, a chemicd union may be effected be- 

 tween them : thus azote and oxygen will yield the nitrous 



acid. 



