Animal  Chemistry. 
389 
Such  are  the  scanty  lights  thrown  lately  by  chemistry  on  the 
culture  of  crops,  but  the  principles  on  which  animals  are  nourished 
have  been  suddenly  brought  into  full  day  by  the  brilliant  dis- 
coveries of  Baron  Liebig.  That  great  chemist  has  shown  that 
the  stomach  of  animals  does  not  compound  their  flesh  from  the 
ingredients  of  their  vegetable  food,  but  finding  that  flesh  ready 
formed  in  the  corn  or  hay,  merely  selects  and  appropriates  it.  This 
substance,  called  gluten  or  albumen,  resembling  the  white  of  an 
egg,  is  found  generally  in  food.  “ Chemists,”  says  Dr.  Play- 
fair,* “ were  surprised  to  discover  that  this  body  never  varies  in 
composition,  that  it  is  exactly  the  same  in  corn,  beans,  or  from 
whatever  plant  it  is  extracted.  But  their  surprise  was  much 
increased  when  they  remarked  that  it  is  quite  identical  with  the 
flesh  and  blood  of  animals.  It  consists  of  carbon,  hydrogen, 
nitrogen,  and  oxygen,  and  in  the  very  same  proportion  in  100 
parts.  So  much  so,”  he  goes  on,  “ that  if  you  were  to  place  in 
a chemist’s  hands  some  gluten  obtained  from  wheat-flour,  dry 
albumen  from  an  egg,  a fragment  of  the  flesh  of  an  ox,  or  of 
dried  blood,  he  would  tell  you  that  they  are  precisely  the  same.” 
He  adds  the  following  analyses: — 
Gluten 
Casein 
Albumen 
from  Flour. 
from  Peas. 
from  Eggs. 
Ox  Blood, 
Ox  Flesh. 
lloussingault. 
Scherer. 
Jones. 
Playfair. 
Carbon  .... 
54-2 
54-138 
55-000 
54-35 
54-12 
Hydrogen  . . . 
7-5 
7‘156 
7-073 
7-50 
7-89 
Nitrogen  .... 
13-3 
15-672 
15-020 
15-76 
15-67 
Oxygen  .... 
21-4 
23-034 
22-007 
22-39 
22-32 
100 
© 
© 
1 r— " 
100 
100 
100 
Analyses  not  differing  from  each  other  more  than  the  analyses 
of  the  same  substance  usually  do.  The  gluten  or  casein  of  the 
flour  or  peas,  which  we  may  call  fibrine,  taken  into  the  stomach, 
and  thence  into  the  veins,  becomes  blood,  and  the  blood  passing 
from  the  veins  becomes  flesh,  without  change,  just  as  a house  is 
built  up  with  stones  from  a quarry.  The  muscles  of  the  ox  are 
woven  invisibly  from  the  fibrine  of  grass,  as  linen  visibly  from 
the  fibres  of  flax. 
This  is  an  undoubted  truth,  and  a great  discovery  of  Liebig's. 
Another  discovery  is  so  well  known  that  it  need  only  be  men- 
tioned. Besides  fibrine,  which  becomes  meat,  vegetable  food 
contains  other  substances,  gum,  starch,  sugar.  Ail  these  are 
without  nitrogen,  and  consist  of  charcoal  {carbon),  with  the  ele- 
ments of  water  {oxygen  and  hydrogen),  that  is  of  the  substance  of 
wood.  Liebig  has  shown  that  in  the  animal  body  they  are  used 
as  wood,  being  absorbed,  combined  with  oxygen,  and  exhaled  as 
carbonic  acid.  In  the  words  of  Dr.  Playfair,  “ The  body  is  the 
* Applications  of  Physiology  to  the  Rearing  and  Feeding  of  Cattle.  Journal,  vol.  iv. 
p.  215. 
