ORGANIC CHEMISTRY. 295 



412. Molecules In Organic Bodies. Organic substances 

 arc generally more complex in their constitution than min- 

 eral substances, their molecules containing a far larger 

 number of atoms. For example, while carbonic anhydride 

 has in each molecule one atom of carbon and two of oxy- 

 gen, CO 2 , and sulphuric acid two of hydrogen, one of sul- 

 phur, and four of oxygen, H 2 SO 4 , making 7 atoms in the 

 molecule, each molecule of tartaric acid contains 16 atoms, 

 as indicated in the formula H 2 C 4 H 4 O 6 ; while a molecule of 

 starch is believed to contain 63 atoms (starch = C 18 H 30 O 15 ), 

 and of stearin 173 atoms. 



One of the most complex of organic bodies is albumen, 

 which is supposed to contain several hundred atoms in a 

 molecule ; but this number will probably be reduced when, 

 its composition is better understood. 



413. Instability. Organic substances are unstable com- 

 pounds, that is, very easy to decompose, because they are 

 so complex. It is with them as it is with machinery. The 

 greater the complication, the greater is the liability to 

 derangement. The more atoms there are in a molecule, 

 therefore, the more easily can it be broken up, and the 

 more kinds of atoms there are in it the greater is the lia- 

 bility to this result. Not only do organic substances differ 

 from the inorganic in this respect, but they differ among 

 themselves. We have a good example of this in bleach- 

 ing. The coloring matter of the cloth is broken up and 

 dissipated, while the cloth itself remains, for the simple rea- 

 son that the molecule of the coloring matter is composed 

 of four elements carbon, hydrogen, oxygen, and nitrogen 

 M'hile that of the vegetable tissue, the substance of the 

 cloth, is composed of only three carbon, hydrogen, and ox- 

 ygen. The more complex substance is decomposed first ; 

 but if the process be continued after the cloth has become 

 white that is, after the coloring substance is all destroyed 



