306 SOLID PARTS OF ANIMALS. 



They contained 1-8 per cent, of ashes. The constituents obtain- 

 ed were 



1. Of the soft downy portion. 



Carbon, . 50-434 and 52-470 



Hydrogen, . 7-110 



Azote, . 17-682 



Oxygen, . 24-774 



100-000 



2. The quill portion. 

 Carbon, . 52-427 

 Hydrogen, . 7-213 

 Azote, . 17-893 

 Oxygen, . 22-46 



100-000 



The constitution of both is obviously the same. Scherer repre- 

 sents it by the formula C 48 H 39 Az 7 O 16 . By this formula they 

 contain an atom less of oxygen than hair or horns. 



CHAPTER XVII. 



OF HORNS, NAILS, AND SCALES. 



Horns are well-known bodies attached to the foreheads of 

 oxen, sheep, and various other animals, and are obviously in- 

 tended for weapons of defence. They cover an elongation of 

 bone which rises from the os frontis. The portion of horny 

 matter nearest the forehead is the thinnest, and it constantly in- 

 creases in thickness as it advances to the extremity, where it is 

 thickest. It is translucent, and when very thin, has even a de- 

 gree of transparency, and has been used as a substitute for glass 

 in windows. Its colour is sometimes yellowish-grey, and some- 

 times almost black. It is capable of receiving a good polish, and 

 its lustre is resinous. 



It is not very hard, and is easily rasped down by a file or rasp. 

 During this process it emits a disagreeable smell. When heated 

 a little above 212, it becomes very soft, without undergoing de- 



