184 
VARIETIES. 
traction  of  the  ethereal  oils,  the  small  quantities  of  which  are  mixed  in  the 
flowers  with  such  large  quantities  of  other  vegetable  juices  that  it  requires 
about  GOO  lb.  of  rose-leaves  to  win  one  ounce  of  otto  of  roses,  demands  a 
very  careful  treatment.  The  French,  favored  by  their  climate,  are  the 
most  active,  although- not  always  the  most  careful,  preparers  of  perfume; 
half  the  world  is  furnished  by  this  branch  of  their  industry. — Ibid. 
The  Extraction  of  Potato  Starch* — In  the  manufacture  of  this  article  a 
considerable  quantity  of  the  product  is  lost  owing  to  the  strong  affinity  the 
starch  lias  for  the  fibre  of  the  potato.  From  M.  Anthon's  experiments  on 
the  subject,  it  appears  that  the  manufacturer  only  extracts  two  thirds,  and 
that  the  remaining  third  is  left  in  the  pulp.  M.  Anthon  suggests  that 
this  third  may  be  utilized  by  converting  it  into  sugar,  by  means  either  of 
malt  or  dilute  sulphuric  acid.  By  employing  10  per  cent,  of  the  acid  to 
the  dry  fibre,  the  saccharification  is  completed  in  about  two  hours  and  a 
half ;  but  if  only  3  or  4  per  cent,  of  acid  is  used,  the  boiling  must  be  con- 
tinued for  at  least  five  hours.  Ten  per  cent,  of  malt  effected  the  conver- 
sion in  six  hours.  The  result  as  to  the  quality  and  quantity  of  sugar  pro- 
duced is  the  same  whether  it  is  obtained  by  malt  or  sulphuric  acid. — 
Chem.  News,  from  Qhemisch  Central  Blatt,  1859. 
Cubilose. — M.  Payen  has  submitted  to  a  chemical  examination,  the  sub- 
stances contained  in  the  bird's  nests  which  are  used  by  the  Chinese  as  an 
aliment,  and  form  among  the  Oriental  nations  the  object  of  a  large  com- 
merce. These  nests,  as  is  well  known,  are  constructed  by  a  species  of 
swallow,  which  the  French  term  Salangane.  The  quantity  of  nests  ex- 
ported yearly  from  the  Indian  archipelago  is  estimated  at  242,000  lb. 
English.  The  value  of  the  substance  is  from  100  to  150  francs  a  pound. 
In  Paris,  these  swallow  nests  sell  sometimes  as  high  as  400  francs  a  pound, 
or  5  or  6  francs  per  nest.  They  are  sold  ready  for  eating.  Many  natural- 
ists think  that  the  nests  are  composed  of  the  spawn  of  fish,  or  of  a  mixture 
of  various  zoophytes  ;  others  think  they  are  made  of  a  certain  juice  which 
exudes  from  some  unknown  tree,  or  that  they  are  constructed  with  lichens 
and  gelatinous  algae.  It  appears  certain,  however,  that  the  swallows  pro- 
duce at  the  time  of  nidification  a  mucilaginous  liquid,  secreted  from  their 
salivary  glands,  or  by  the  glands  of  one  of  their  stomachs,  in  the  same 
manner  that  the  swallows  of  Europe  secrete  a  viscous  liquid  with  which 
they  cement  together  the  materials  of  their  nests  in  the  window  corners 
of  our  houses. 
M.  Payon's  investigations  show  that  such  is  the  case;  the  agglutinative 
and  alimentary  principle  of  the  Salangane's  nest  sometimes  forms  the 
greater  part,  or  even  the  whole  of  the  nest,  and  is  a  peculiar  secretion 
analogous  to  animal  mucus  containing  nitrogen  (9-52  per  cent)  and  sul- 
j)hur,  devoid  of  organisation,  sinking  in  water,  and  dissolving  almost  en- 
