ON  CHEMISTRY  APPLIED  TO  THE  ARTS. 
257 
ter  ;  for,  as  you  see  by  this  specimen,  the  mineral  matter  has 
been  entirely  removed  without  deforming  the  animal  texture. 
Further,  in  the  foetus  it  is  found  that  the  bones  contain  nearly 
the  same  proportions  of  animal  and  mineral  matters  as  those  of 
the  adult.  Also,  it  has  been  observed  by  M.  Flourens,  and  other 
eminent  physiologists,  that  the  wear  and  tear  of  bones  during 
life  is  repaired  by  the  formation  of  new  bone  on  the  exterior  sur- 
face of  the  bone,  while  the  old  substanace  is  removed  through  the 
interior  duct,  and  that  the  composition  of  the  new  layer  is  the 
same  as  that  of  the  original  bone.  Let  us  now  proceed  to  examine 
the  chemical  properties  of  the  various  substances  composing 
bones,  and  some  of  the  various  applications  which  they  receive 
in  arts  and  manufactures.  The  general  composition  of  bones  may 
be  considered  to  be  as  follows  : — 
Bones. 
(  Blood-vessels  ....  1 
\  Osseine         ....  32 
(Fatty  Matters       ...  9 
"Water  ....  8 
Phosphate  of  lime   ...  38 
<  Phosphate  of  magnesia    .        .  2 
Carbonate  of  lime  .       .  8 
(^Various  salts  .       .  2 
Organic 
Substances 
Mineral 
Substances. 
100 
504 
6-5 
16-9 
26-2 
The  above-named  matter,  osseine^ — 
C  .       .  . 
H.  . 
N. 
0  . 
and  which  has  been  erroneously  called  gelatine,  is  insoluble  in 
water,  weak  acids,  and  alkalies,  whilst  gelatine  presents  proper- 
ties directly  reverse.  But  what  has  led  to  this  popular  error  is 
that  osseine,  when  boiled  in  water,  becomes  converted  into  the 
isomeric;  substance  commonly  called  gelatine.  As  I  shall  have  to 
dwell  on  this  substance  at  some  length  in  my  next  two  lectures,  I 
will  not  detain  you  now  further  than  to  state  that  osseine  is  ob- 
tained from  bones  by  placing  them  in  weak  hydrochloric  acid, 
which  dissolves  the  phosphate  of  lime  and  other  mineral  salts, 
washing  the  animal  matter  (osseine)  until  all  acid  is  removed, 
17 
