MOLECULAR  DISSYMMETRY  OF  ORGANIC  PRODUCTS.  109 
cal  wood,  and  in  right  lines.  All  the  mechanical  conditions 
of  the  two  systems  will  be  the  same.  It  will  be  no  longer  so 
from  the  moment  these  same  helices  shall  be  associated  with 
blocks,  themselves  shaped  in  helices  of  the  same  direction,  or  of 
opposite  directions. 
X. 
Here  is  a  very  interesting  application  of  the  facts  which  I 
have  just  submitted. 
Seeing  right  and  left  tartaric  acids  become  thus  dissimilar 
solely  in  virtue  of  the  rotary  power  of  the  base,  there  was  room 
to  hope  that  from  this  very  dissemblance  would  result  chemical 
forces  capable  of  balancing  the  mutual  affinity  of  these  two 
acids,  and  consequently  a  chemical  means  of  separating  the  two 
elements  of  paratartaric  acid.  I  long  sought  without  success ; 
but  I  succeeded  in  it  by  the  aid  of  two  new  bases,  isomerics  of 
quinine  and  cinchonine,  and  I  obtain  very  easily  without  the 
smallest  loss,  by  the  aid  of  these  latter,  quinicine  and  cincho- 
nicine. 
I  prepare  the  paratartrate  of  cinchonicine  by  neutralizing 
the  base,  then  adding  as  much  acid  as  was  required  for  its 
neutralization,  I  crystallized,  and  the  first  crystallizations  are 
formed  of  left  tartrate  of  cinchonicine  perfectly  pure.  All 
the  right  tartrate  remains  in  the  liquid  because  it  is  more 
soluble.  Then  itself  is  crystallized,  and  under  a  different  as- 
pect, because  it  has  not  the  same  crystalline  form  as  the  right 
[qu.  left?]  One  would  suppose  that  he  had  to  deal  with  the 
crystallization  of  two  very  distinct  salts,  of  unequal  solubility. 
XL 
But  the  dissemblance  of  the  properties  of  corresponding  right 
and  left  bodies  when  submitted  to  dissymmetric  forces,  appears 
to  me  to  be  of  the  highest  interest,  in  connection  with  the  ideas 
it  suggests  on  the  mysterious  cause,  which  presides  over  the 
dissymmetric  disposition  of  atoms  in  natural  organic  substances. 
Why  this  dissymmetry?  why  such  a  dissymmetry  in  preference 
to  its  inverse  ? 
Recur  with  me  in  thought  to  the  epoch  when,  having  recog- 
nised the  absolute  identity  of  the  physical  and  chemical  proper- 
ties of  corresponding  right  and  left  bodies,  I  had  no  idea,  not 
