394 
GLEANINGS — CHEMICAL  AND  PHARMACEUTICAL. 
If  dissolved  in  concentrated  sulphuric  acid  and  the  solution 
spread  out  upon  a  porcelain  plate,  it  is  colored  violet  by  nitric 
acid  of  about  the  sp.  gr.  1*2.  Lactucon  and  colchicin  show  the 
same  coloration.  But  the  acid  solution  of  the  latter  diluted  with 
water,  assumes  a  beautiful  yellow  red  color  with  a  violet  tinge 
by  potassa,  while  euphorbon  is  precipitated  from  its  acid  solution 
by  water  without  change  of  color.  Elementary  analysis  led  to  the 
formula  C26H2202.  Johnston's  uncrystallizable  indifferent  resin, 
which  is  very  readily  soluble  in  cold  75  per  cent,  alcohol,  has  the 
composition  C2(1H2204.  Euphorbium  contains  about  38  per  cent, 
resin  (acrid  principle),  22  euphorbon,  18  gum,  12  malates  and 
10  per  cent,  inorganic  matter. — (Ibid.,  94-96.) 
Reaction  of  Oxide  of  Copper  with  Guaiac. — Pagenstecher 
observed,  about  30  years  ago,  that  a  cupric  salt  in  the  presence 
of  hydrocyanic  acid  imparts  a  blue  color  to  guaiac  resin.  Ed. 
Schaer  found  that  a  liquid  containing  per  cent,  of  sulphate 
of  copper  and  per  cent,  shows  the  reaction  very  distinctly, 
and  argues  that  this  is  produced  through  a  portion  of  the 
oxygen  of  the  cupric  oxide  present  in  the  modification  of  ozone, 
which  in  the  presence  of  hydrocyanic  acid,  is  induced  to  react 
with  the  resin  of  guaiac.  The  reaction  with  the  same  resin  of 
binoxide  of  lead,  ferric  and  mercuric  oxide  depend  likewise  upon 
the  presence  of  active  oxygen. — (Ibid.,  18  and  19.) 
Traces  of  Ammonia  are  detected  by  Bohlig's  reagent  (mer- 
curic chloride  with  the  addition  of  carbonate  of  potassa)  or  by 
Nessler's  reagent  (mercuric  iodide  dissolved  in  iodide  of  potassium 
with  the  addition  of  potassa).  Rehsteiner  found  that  the  former 
produces,  in  5  minutes,  a  distinct  white  turbidity  in  liquids  con- 
taining one  millionth  part  of  ammonia,  while  the  limits  of  the 
latter  reagent  are  ^^UUTJ,  producing  in  15  minutes  a  faint  yellow 
turbidity.— (Ibid.,  112). 
GLEANINGS  CHEMICAL  AND  PHARMACEUTICAL. 
By  the  Editor. 
Vegetable  organisms  in  the  human  blood. — Dr.  Joseph  G.  Rich- 
ardson, of  Union  Springs,  N.  Y.,  after  numerous  examinations 
of  human  blood,  has  arrived  at  the  conclusion  that  living  organ- 
