Am,  J  our.  Pharm.  \ 
Dec  ,  1880.  i 
Chemical  Notes. 
A  large  terebinth  tree  will  yield  7  to  14  ounces  annually. 
Mathieu's  statement  as  to  the  rapid  hardening  of  this  turpentine  is 
quite  in  accordance  with  the  description  given  in  the  Pharmacugra- 
phia."  It  may  fairly  be  presumed  that  the  Algerian  resin  is  identical 
with  that  originally  collected  in  the  island  of  Chio. 
The  authors  of  the  "  Pharmacographia "  are  of  the  opinion  that 
another  kind  of  terebinth,  ''^  Pistacia  atlantica^''  Desfontaines,  growing 
to  a  large  size  all  over  Northern  Africa,  is  but  a  variety  of  Pistacia 
terebinth  us.,  but  Mathieu  consider*;  them  to  be  distinct  trees.  How- 
ever this  may  be,  he  further  says  that  Pistacia  atlantica  also  affords  an 
abundance  of  the  same  turpentine  as  the  genuine  Pistacia  terehinthus. 
We  may  further  suppose  that  the  supply  of  products  under  notice 
might  be  largely  increased  by  systematically  puncturing  the  bark. 
There  is  thus  a  possibility  of  procuring  any  quantity  of  Chio  tur- 
pentine at  a  moderate  rate,  in  order  to  enable  the  medical  profession  to 
settle  the  question  as  to  the  real  merits  of  this  old  drug,  which  is  sin- 
gularly again  claiming  a  position  in  the  modern  materia  medica. — 
Pharm.  Jour,  and  Trans. ^  October  16,  1880. 
CHEMICAL  NOTES. 
By  Prof.  Samuel  P.  Sadtler,  Ph.D. 
Inorganic  Chemistry.— *S'^/)^r^//(?;z  and  Determination  of  Arsenic. — 
Emil  Fischer  finds  that  the  method  proposed  simultaneously  by 
Schneider  and  Fyfe  for  the  separation  of  arsenic  in  toxkological  exami- 
nations by  distillation  as  trichloride  is  not  generally  used  for  ths  reason 
that  in  the  ordinary  cases  the  arsenic  is  gotten  as  arsenic  acid,  which 
is  not  affected  without  previous  reduction.  He  finds,  moreover,  that 
ferrous  chloride  is  a  reagent  specially  adapted  for  this  reduction,  so  that 
the  arsenic  can  be  readily  converted  into  arsenious  acid  and  then  distilled 
as  trichloride  Thus,  by  distillation  with  hydrochloric  acid  and  ferrous 
chloride,  the  arsenic  is  quickly  and  completely  converted  into  volatile 
trichloride,  while  all  the  other  metals  of  the  sulphuretted  hydrogen 
group,  including  antimony  and  tin,  remain  behind  in  the  liquid  with  the 
iron.  The  estimation  of  the  arsenic  in  the  distillate  may  be  made 
either  gravimetrically  as  trisulphide,  according  to  Bunsen,  or  better 
volumetrically,  after  neutralizing  with  potassium  carbonate  with  iodine 
solution.  The  hydrochloric  acid  solution,  from  which  the  arsenic  is 
to  be  distilled,  may  contain  sulphuric  acid,  but  not  nitric  acid.  Metallic 
39 
