Am.  Jour.  Pharm.\ 
April,  1893.  J 
Linseed  Cake  and  Meal. 
197 
hours  at  100-1050,  and  (3)  when  dried  for  two  hours  at  ioo°  in  an 
atmosphere  free  from  oxygen ;  the  results  should  not  differ.  The 
rancidity  of  the  fat  is  determined  (1)  after  the  fat  has  been  so  long 
dried  that  it  no  longer  has  an  unpleasant  odor,  and  (2)  without  pre- 
vious drying.  The  first  estimation  gives  a  lower  result  than  the 
second,  from  loss  of  volatile  fatty  acids.  The  higher  the  percentage 
of  acid  the  greater  the  difference  in  the  two  experiments ;  the  esti- 
mation of  rancidity  of  linseed  residues  and  in  foods  generally  should 
therefore  be  made  in  the  fat  from  undried  substance.  The  cake  and 
meal  were  also  examined  bacteriologically  ;  large  numbers  of  micro- 
organisms were  found,  but  the  results  give  no  indication  of  the 
quality  of  the  substance  examined,  as  the  nature  (injurious  or  other- 
wise) of  the  micro-organisms  is  not  known. 
A  second  paper  on  the  same  subject,  by  F.  J.  Van  Pesch  contains 
the  following  information :  Only  very  little  of  the  linseed  worked 
in  Holland  is  produced  in  that  country ;  much  is  obtained  from 
Russia,  but  most  from  India.  The  composition  of  samples  of  cake 
examined  at  Wageningen  varied  as  follows:  proteids  (22-37),  fatty 
matter  (6-2-18-5),  starchy  matter  (30),  water  (11-16),  ash  (4-5-8-6), 
and  crude  fibre  (7-3-12-3  per  cent.).  The  average  amount  of 
digestible  matter  (according  to  Kiihn),  would  therefore  be  :  pro- 
teids 26,  fatty  matter  10-4,  and  starchy  matter  24-3  per  cent.  The 
origin  of  the  seed  has  a  great  influence  on  the  quality  of  the  cake. 
According  to  Voelcker,  the  Russian  seeds  contain  most  albumin; 
those  grown  further  south  contain  the  most  fat.  The  method  for 
the  microscopic  examination  of  linseed  was  described  by  Kobus, 
{Landw.  Jahrb.,  1884,  120).  The  chief  weeds  which  occur  in  lin- 
seed are  Polygonum  Convolvulus  and  lapathifolium ;  rape  is  very 
frequent,  whilst  Camelina  dentata,  Galium  Aparine,  Thlaspi  arvense, 
and  Agrostemma  Githago  also  occur.  Less  frequent  are  Brassica 
nigra,  Sinapis  arvensis,  Plantago  lanceolata,  Lolium  and  other  grasses. 
Besides  these  seeds  which  occur  naturally,  stalks  and  sand  are  some- 
times found.  In  Belgium,  rice  meal  and  earth-nut  skins  are  fre- 
quently added. 
Cake  manufactured  by  the  so-called  American  method,  in  which 
the  finely-powdered  seed  is  extracted  by  carbon  bisulphide,  only 
contains  3-4  per  cent,  of  fatty  matter,  and  is  therefore  not  used  in 
Holland.  The  method  employed  for  the  examination  of  cake  is  as 
follows  :  The  sample  is  made  to  pass  through  a  5  mm.  sieve,  and  5 
