Am-j^l£arm'}      Beckfs  Test  for  Cotton-Seed  Oil.  281 
Xow,  to  apply  the  test,  Prof.  Beehi  takes  10  cc.  of  the  oil  to  be  ex- 
amined, adds  1  cc.  of  the  alcoholic  solution  of  silver  nitrate  and  then 
from  8  to  10  cc.  of  the  mixture  of  aniylic  alcohol  and  oil  of  rape  ; 
agitating  strongly  and  then  heating  on  a  water-bath  for  5  or  10  min- 
utes. 
In  the  case  of  pure  oils,  the  color  remains  the  same,  as  it  was  after 
the  addition  of  the  reagents.  In  the  event  that  sophistication  has 
been  practiced  with  cotton-seed  oil,  there  will  be  produced  a  brownish 
color,  or  turbidity,  of  a  varying  grade,  from  a  very  light  brown  to  a 
deep  maroon  or  black,  according  to  the  quantity  of  cotton  oil  present. 
With  these  data  furnished  by  Prof.  Bechi,  and  after  having  assisted 
in  experiments  made  by  him  in  support  of  his  method,  the  Commis- 
sion instituted  a  series  of  long  and  diligent  personal  experiments, 
numbering  over  200,  in  the  chemical,  biological  and  hygienic  lab- 
oratory of  the  Eoyal  Institute;  adhering  strictly  to  the  rules  as 
laid  clown,  measuring  exactly,  in  each  instance,  the  quantities  of  oils 
and  reagents,  and  using  tubes  of  equal  diameters  or,  in  one  word,  em- 
ploying the  same  conditions  in  all  experiments,  in  order  to  render  the 
result  truly  comparative. 
The  oils  used  were  furnished  in  part  by  Prof.  Bechi  and  in  part  by 
this  Commission  ;  looking,  especially,  for  those  olive  oils  of  whose 
genuine  nature  there  could  be  no  possible  doubt  and  then,  secondly, 
taking  good  olive  oil  containing  cotton  oil.  Several  of  the  olive  oils 
were  from  other  countries  (Spain,  France,  Tunis,  Dalmatia  and 
Malta,  etc.),  but  the  greater  number  were  from  various  parts  of 
Italy.  Some  were  recent  and  some  old,  others  pure  of  la,  2a,  3a, 
quality  and  others  were  rancid. 
In  order  to  ascertain  if  the  reaction  outlined  by  Bechi  was  peculiar 
to  cotton-seed  oil  addition,  alone,  the  Commission  foimd  it  necessary  to 
extend  their  experiments  upon  other  oils,  vegetable  and  animal, 
alone  and  admixed  with  pure  olive  oil. 
Every  experiment  made  was  in  doubles  or  triples,  that  is  two  sani 
pies  of  the  oil  (marked  Xo.  1  and  No.  3)  and  another  sample  of  the 
oil  (marked  Xo.  2),  which  had  added  to  it  cotton-seed  oil  in  a  certain 
proportion  j  subjecting  Xo.  1  and  Xo.  2  samples  to  the  heat  of  boil- 
ing water,  after  the  addition  of  the  reagents  and  leaving  Xo.  3  sample 
without  exposure  to  heat,  in  order  to  compare  the  colors  of  Xos.  1 
and  2  with  that  of  Xo.  3.  The  experiments  were  then  especially 
directed  toward  the  mixture  of  olive  oil  with  oil  of  cotton-seed.  The 
