. III. DIST. CHAR. Mode. 51 



which the introduction of the mineral particles is 

 effected. f The bodies impregnated are either 

 such as,, at the commencement of the process, were 

 in their original state, or such as had previously 

 been subjected to privation (III. 2. ) or conversion 

 (III. 3.) Thus bones with and without the phosr 

 phoric add, are found replete with mineral matter * 

 also shells, corals, and other marine productions of 

 the same class, more or less altered from their origi- 

 nal nature. Wood and other vegetable substances, 

 either carbonized, or only slightly changed from their 

 recent state, also occur penetrated in a similar man- 

 ner. 



Impregnated conservata are either saline, metal- 

 lic,^ earthy, or inflammable. 



B. 5. SUBSTITUTION (Substitutio). In this 

 process only the form of the original is preserved ; 

 mineral or inorganic matter having taken place 

 of that which was organic. 



Miner alm&y be substituted^ the place of organic 

 matter, under, 1. Redintegration, or a renewal of 



f Impregnation is the first stage of the process of intromission^ 

 under which the formation of intrinsic petrifactions is effectecj. 

 According to the same view of the subject, conversion is the com- 

 mencement of transmutation : and, we may add, that as in all in- 

 stances, the total decay and removal of the organic body must pre- 

 cede redintegration, privation seems more particularly connected 

 with this last mentioned mode of petrifaction than with either of 

 the foregoing. 



It The metallic are most common in veins. 



