FORMATION OF FAT. 87 



starch, C 24 H 20 O 20 , the elements of 9 equivalents of car- 

 bonic acid are separated, there will remain a compound 

 containing, for 15 equivalents of carbon, 20 of hydro- 

 gen and 2 of oxygen ; for 



C 24 H 20 Oo = C 9 O 18 -f- C 15 H 20 O 2 . 



Or, if we assume that oxygen is separated from starch 

 in the form both of carbonic acid and water, then, after 

 subtracting the elements of 6 equivalents of water and 

 6 of carbonic acid, there would remain the compound 

 C 18 H 14 2 ; for 



C 24 H 20 20 = C 6 12 + H 6 6 + C 18 H 14 O 2 . 



Assuming, then, the separation of oxygen in either 

 of these forms, it remains to be decided whether the 

 carbonic acid and water given off were contained, as 

 such, in the starch, or not. 



If they were ready formed in the starch, the separa- 

 tion might occur without the disengagement of heat ; 

 but if the carbon and hydrogen were present in any 

 other form in the starch (or in the compound from 

 which the fat was produced) 4 it is obvious that a change 

 in the arrangement of the atoms must have occurred, in 

 consequence of which the atoms of the carbon and of 

 the hydrogen have united with those of the oxygen, to 

 form carbonic acid and water. 



Now, so far as chemical researches have gone, our 

 knowledge of the constitution of starch, and of the va- 

 rieties of sugar, will justify no other conclusion than 

 this, that these substancfes contain no ready formed car- 

 bonic acid. 



We are acquainted with a large number of processes 



