296 
Varieties. 
f  Am.  Jour.  Pha.r»j 
t    Jane  1, 1874. 
If  passed  through  water  for  a  longer  time,  the  loss  of  ozone  is  greater.  The 
loss  of  ozone  is  the  more  considerable  the  longer  the  gas  is  in  contact  with  the 
water,  and  the  greater  the  surface  exposed.  (2)  Ozone  is  absorbed  by  water 
in  a  considerable  degree,  even  at  the  ordinary  temperature  of  the  atmosphere. 
(3)  On  passing  dry  ozonized  oxygen  through  water  much  more  ozone  disappears 
than  is  absorbed  by  the  water.  The  decrease  of  the  proportion  of  ozone  is, 
therefore,  only  very  slightly  determined  by  absorption,  but  must  be  considered 
as  a  consequence  of  the  destructive  action  of  water.  (4)  Ozone  does  not  con- 
vert water  into  peroxide  of  hydrogen.  As  regards  the  loss  of  ozone  in  ozonized 
oxygen  gas,  on  standing  for  a  longer  or  shorter  time  in  contact  with  water,  the 
author  concludes — (1)  if  oxonized  oxygen  is  left  in  contact  with  water,  the 
ozone  is  gradually  converted  into  ordinary  oxygen.  In  three  days  the  original 
proportion  of  ozone  is  reduced  to  one-half,  and  in  fifteen  days  mere  traces  of 
ozone  remain.  (2)  The  transformation  of  ozone  into  oxygen,  in  contact  with 
water  and  at  common  temperatures,  is  attended  with  an  increase  of  bulk. — 
Ghem.  News,  from  Ann.  d.  Chem.  u.  Pharmn  1874,  Jan. 
Formation  of  Gum  in  Fruit-Bearing  Trees. — E.  Prillieux. — In  the  wood  of 
a  tree  diseased  with  gum,  a  great  number  of  vessels  are  always  seen  more  or 
less  completely  filled  with  gum;  sometimes  they  are  entirely  filled  to  a  certain 
length,  and  sometimes  the  gum  only  forms  a  coating  either  upon  all  the  periphery 
or  only  on  one  side.  The  gum  first  shows  itself  in  very  small  drops,  which 
gradually  increase  in  size  and  touch  each  other,  forming  small  irregular  masses. 
Recent  German  observers  have  stated  that  the  formation  of  the  gum  is  due  to* 
the  disorganization  and  transformation  of  the  internal  part  of  the  wall  of  the 
vessel,  but  the  author  has  come  to  an  opposite  conclusion.  In  examining  the 
wood  of  an  apricot  tree  from  which  large  masses  of  gum  were  extracted,  it  wa& 
found  that  the  vessels  were  marked  with  areolated  punctures,  and  with  a  spiral 
line  due  to  a  thickening  of  the  membrane  ;  also  that  the  surfaces  of  the  masses  of 
gum  were  marked  with  deep  furrows  corresponding  with  the  spiral  lines  of  the 
vessel-wall,  and  even  with  small  projections  according  with  the  punctures.  It 
is  thus  certain,  in  the  author's  opinion,  that  the  gum  has  poured  into  the  interior 
of  the  vessel,  and  that  the  marks  upon  it  are  imprinted  from  the  vessel  wall. 
In  the  production  of  gum  in  the  cellules  by  the  transformation  of  starch,  it 
has  been  observed  that,  on  the  first  appearance  of  gum  in  the  cellule,  the 
unchanged  starch  gathers  into  small  masses,  around  which  forms  a  thin  coating 
of  gum.  Gradually  the  starch  diminishes,  while  the  coating  of  gum  increases, 
until  at  last  the  starch  disappears  altogether,  leaving  generally  a  vacant  space 
in  the  centre  of  the  mass  of  gum. 
Often  the  gum  produced  in  such  considerable  quantity  is  formed  neither  in 
the  vessels  nor  in  the  cellules,  but  in  the  spaces  between  the  young  tissues,, 
generally  between  the  wood  and  the  bark,  yet  often  also  at  different  depths  in 
the  wood.  These  gum-spaces  grow  at  the  expense  of  the  neighboring  tissues, 
which  suffer  important  modifications :  the  cambium,  instead  of  producing 
woody  fibre,  forms  cellules  in  which  abundance  of  starch  are  deposited,  which 
starch  subsequently  becomes  converted  into  gum. — Jour.  Chem.  Soc.  [Lond.)? 
April,  1874,  from  Compt.  Rend.,  lxxviii,  135. 
