466  Researches  on  Albumin.  {  ^™j£rxa 
pound  C12H24N204  gave  always  the  same  analytical  numbers,  from 
which  it  is  fair  to  suppose  that  it  has  an  independent  existence.  The 
supposition  is  moreover  strengthened  by  the  fact  that  similar  results 
were  obtained  with  the  lower  homologues  containing  n,  10,  9,  and 
even  7  atoms  of  carbon. 
For  these  latter  bodies,  the  name  glucoproteins  has  been  adopted,  on 
account  of  their  sweet  taste  ;  they  crvstallize  less  easily  than  the  leu- 
cins, especially  the  lower  terms  j  they  are  very  soluble  in  water,  but 
almost  insoluble  in  cold  absolute  alcohol  ;  hot  alcohol  of  90  per  cent, 
however  dissolves  them  with  ease. 
Another  substance  resulting  from  the  decomposition  of  albumin, 
which  is  produced  in  important  quantity,  is  a  yellow  viscous  body 
obtained  by  precipitating  certain  mother-liquors  from  which  leucins 
have  been  crystallized  by  ether.  Dried  at  1200,  it  is  converted  into  a 
transparent  amorphous  mass,  which  on  analysis  gives  numbers  com- 
prised between  the  formulae  C5H9N02  and  C4H7N02,  very  often  sensi- 
bly approximating  to  the  formula  C9H16N204 ;  it  appears  in  fact  to  be 
constituted  in  great  part  of  butyric  leucin  with  an  admixture  of  some 
superior  homologue. 
The  longer  the  action  of  baryta  on  albumin  is  continued,  and  the 
more  concentrated  the  solution,  the  greater  is  the  proportion  of  leucins 
and  of  leuceins  formed,  whilst  under  the  contrary  conditions  the  inter- 
mediate bodies  or  glucoproteins  constitute  the  bulk  of  the  fixed  residue, 
representing  the  initial  terms  of  the  hydration  of  albumin.  Under  all 
circumstances,  caproic  leucin  and  tyrosin  appear  to  be  the  ultimate 
term  of  the  decomposition. 
The  mechanism  of  the  reaction  would  therefore  appear  to  admit  of 
the  following  explanation :  The  albuminoid  molecule  losing  ammonia 
and  carbon  as  carbonic,  oxalic  and  acetic  acids,  and  assimilating  water, 
as  converted  into  a  comparatively  simple  mixture  of  glucoproteins, 
C11H2nN204,  containing  as  its  principal  term  C9H13N204.  By  the  pro- 
longed action  of  baryta  and  a  high  temperature,  these  glucoproteins 
split  up  partly  into  leucins  and  leuceins,  and  partly  into  double  com- 
pounds, formed  by  the  union  of  glucoproteins  and  leuceins  with  the 
leucins. 
The  leuceins  may  perhaps  be  regarded  as  amido-acids  of  the  acrylic 
or  of  an  isomeric  series.    Thev  reduce  ammoniacal  silver  nitrate  on 
