44 
Essence  of  Senna  Pods. 
Am.  Jour.  Pharm. 
Jan.,  1890. 
reached  Glasgow,  which,  on  examination,  was  found  to  be  adulterated 
with  cotton-seed  oil. 
The  adulterant  is  probably  what  is  known  as  "  blown  "  cotton-seed 
oil,  which  is  made  by  blowing  warm  air  through  the  oil.  Great  heat 
is  thereby  developed,  and  the  oil  increases  in  density  and  viscosity. 
The  presence  of  this  oil  cau  be  detected  by  my  modification  of  the 
nitrate  of  silver  test,  which  is  applied  as  follows  : — 
1.  Make  a  test  solution  containing  five  parts  of  silver  nitrate  and 
one  part  of  nitric  acid  (specific  gravity  1*42)  in  one  hundred  parts  of 
rectified  spirit  (specific  gravity  *838). 
2.  Pour  about  100  grains  of  the  oil  under  examination  into  a  dry 
test  tube,  about  half-an-inch  in  diameter,  add  to  it  10  grain  measures 
of  the  above  test  solution,  and  place  the  tube  in  boiling  water  fur  five 
minutes. 
Castor  oil  assumes  a  pale  yellow  color,  but  the  presence  of  cotton- 
seed oil  causes  it  to  become  deep  red. 
In  conclusion,  I  would  just  add  that  the  quantitative  petroleum 
ether  test  is  capable  of  much  further  development,  but  being  tied  for 
time  I  have  not  had  an  opportunity  of  fully  working  it  out. 
ESSENCE  OF  SENNA  PODS.1 
By  C.  Symes,  Ph.D. 
Nowadays,  when,  like  the  Athenians  of  old,  we  are  constantly 
looking  for  something  new,  it  is  rather  gratifying  to  recognize  the 
reintroduction  of  a  drug  which  can  claim  antiquity  as  one  of  its 
virtues.  Not  only  were  senna  pods  known,  but  for  their  properties 
were  recognized,  a  century  or  two  ago ;  bat  as  far  as  I  can  gather 
they  have  not  been  popular  at  any  period  until  quite  lately. 
Dr.  Keith,  after  giving  them  an  extended  trial,  recommended  them  to 
Dr.  Macfarlan,  who,  on  gaining  experience  of  their  utility  as  an  aperient, 
contributed  a  note  on  the  subject  which  was  published  in  the  Lancet 
of  July  27  last.  Soon  after  this  a  parcel  which  had  lain  on  our 
shelves  undisturbed  for  nearly  twelve  months  was  brought  into  use 
on  a  few  ounces  of  a  concentrated  infusion  being  applied  for.  This 
1  Read  at  a  meeting  of  the  Liverpool  Chemists' Association  held  on  November 
7,  1889.    Reprinted  from  the  Chemist  and  Druggist,  November  9,  1889. 
