THEIR MODE OF ACTION. 363 



utmost that we can thence infer is, that those glo- 

 bules have taken no part in the process of decom- 

 position. All the phosphate of lime may be 

 removed from bones, leaving them transparent 

 and flexible like leather, without the form of the 

 bones being in the smallest degree lost. Again, 

 bones may be burned until they be quite white, and 

 consist merely of a skeleton of phosphate of lime, 

 but they will still possess their original form. In 

 the same way processes of decomposition in the 

 blood may affect individual constituents only of 

 that fluid, which will become destroyed and disap- 

 pear, whilst its other parts will maintain the original 

 form. 



Several kinds of contagion are propagated through 

 the air : so that, according to the view already men- 

 tioned, we must ascribe life to a gas, that is, to an 

 aeriform body. 



All the supposed proofs of the vitality of conta- 

 gions are merely ideas and figurative representa- 

 tions, fitted to render the phenomena more easy of 

 apprehension by our senses, with out explaining them. 

 These figurative expressions, with which we are so 

 willingly and easily satisfied in all sciences, are the 

 foes of all inquiries into the mysteries of nature ; 

 they are like the fata morgana, which show us 

 deceitful views of seas, fertile fields, and luscious 

 fruits, but leave us languishing when we have most 

 need of what they promise. 



It is certain that the action of contagions is the 



