METHOD  OF  DRYING  GLUTINOUS  SUBSTANCES.  75 
until,  finally,  the  latter  corresponds  in  its  hygroscopic  state 
with  that  of  the  desiccating  agent.  The  thorough  wetting  in 
this  manner,  of  the  constituent  particles  of  the  substance  to  be 
dried,  which  of  course  must  be  those  insoluble  in  an  ethereal 
liquid,  prevents  their  sticking  together,  and  the  original  ap- 
pearance is  retained  when  dry. 
Gum  separated  by  precipitating  the  aqueous  solution  with 
alcohol,  gives  an  amorphous  white  mass  of  very  slight  adhe- 
siveness, and  with  no  trace  of  the  common  glass-like  condition. 
The  so-called  diastase,  or  the  body  obtained  by  precipitating 
the  extract  of  malt  with  alcohol,  deprived  of  water  under 
ether,  forms  spongy  and  very  light  granules.  In  this  state  it 
retains  its  effect  upon  starch.  The  microscopical  examination 
of  starch  paste  dried  by  this  process  leaves  scarcely  a  doubt 
that  the  starch  grains  exist  in  paste  in  a  state  only  of  extra- 
ordinary expansion,  and  not  in  that  of  actual  solution.  Hops 
give  a  mass  similar  to  diastase,  but,  however,  no  longer  capable 
of  producing  fermentation. 
The  organs  of  plants  dry  rapidly  under  this  treatment,  com- 
monly retaining  their  color,  unless  unusually  delicate.  Taken 
from  the  ether,  they  soon  become  moist  again  in  the  air,  and 
rapidly  lose  their  color,  which,  by  a  continuance  in  the  liquid, 
appears  remarkably  fine. 
The  behaviour  of  animal  productions  under  this  method  of 
drying  is  of  especial  interest.  It  may  be  remarked  that,  gene- 
rally, while  vegetable  matters  are  distinguished  by  their  great 
brittleness  in  the  dry  state,  those  of  animal  origin  are  charac- 
terized by  a  remarkable  toughness,  which  reaches  its  highest 
degree  in  the  fibrous  formations  of  the  skin.  The  pliability 
of  thick  skin  dried  in  ether  over  chloride  of  calcium  is  very 
extraordinary.  Other  animal  preparations  at  the  same  time 
preserve  their  original  form  in  the  dry  state,  the  usual  con- 
traction of  the  parts  being  thus  avoided.  The  whole  intestines 
of  a-  young  dog,  treated  in  this  manner,  formed  a  remarkable 
anatomical  preparation,  in  which  the  delicate  structures  were 
preserved  in  the  most  complete  manner  upon  drying.  The 
lungs  and  liver,  to  preserve  which  vain  attempts  have  hitherto 
been  made,  formed  a  light  spongy  mass,  retaining  completely 
