What is "hartshorn shavings"

Hartshorn \Harts"horn`\ (-h[^o]rn`), n.

1. The horn or antler of the hart, or male red deer.

2. Spirits of hartshorn (see below); volatile salts.

   Hartshorn plantain (Bot.), an annual species of plantain ( Plantago Coronopus); -- called also buck's-horn.
   --Booth.

   Hartshorn shavings, originally taken from the horns of harts, are now obtained chiefly by planing down the bones of calves. They afford a kind of jelly.
   --Hebert.

   Salt of hartshorn (Chem.), an impure solid carbonate of ammonia, obtained by the destructive distillation of hartshorn, or any kind of bone; volatile salts.
   --Brande & C.

   Spirits of hartshorn (Chem.), a solution of ammonia in water; -- so called because formerly obtained from hartshorn shavings by destructive distillation. Similar ammoniacal solutions from other sources have received the same name.