444  Tropical  Fruits.  { AmdStT,\mATm' 
the  suspected  urine  give  a  deeper  violet  than  the  normal  specimen,  it 
may  be  considered  as  diabetic. 
2.  The  urine  under  examination  is  diluted  with  water  to  from  four 
to  six  hundred  times  its  volume.  Even  in  this  enormous  dilution 
diabetic  urine  will  sharply  respond  to  the  reactions  of  the  tests  de- 
scribed, while  normal  urine  would  give  no  result  when  diluted  to  four 
hundred  times  its  volume. 
After  carefully  studying  the  various  tests  for  sugar  in  urine,  F. 
Penzoldt  came  to  the  conclusion  that  the  fermentation  test  is  worthy 
of  the  greatest  confidence  in  doubtful  cases.  All  experiments,  how- 
ever, seem  to  show  that  the  two  new  tests  are  decidedly  more  certain 
than  the  fermentation  test.  They  leave  but  one  thing  to  desire  :  they 
do  not  enable  a  distinction  to  be  made  between  glucose  and  levulose, 
and  although  the  sugar  found  in  urine  will  in  nearly  all  cases  be  glu- 
cose, yet  various  instances  have  occurred  in  which  levulose  was  de- 
tected also. — Phila.  Med.  Times,  Aug.  7,  1886  ;  Monatshefte  fur 
Chemie. 
TEOPICAL  FRUITS.1 
By  D.  Morkis, 
Assistant-Director,  Koyal  Gardens,  Kew. 
Amongst  objects  of  productive  industry  receiving  attention  at  pres- 
ent in  our  colonial  possessions,  tropical  fruits  are  at  once  the  newest 
and  most  interesting  of  all.  Many  of  these  fruits  are  practically  un- 
known in  England  in  a  fresh  state,  and  hence  before  tropical  fruits  are 
largely  consumed  here,  it  is  necessary  to  diffuse  knowledge  respecting 
them,  and  to  render  them  as  familiar  to  English  home  people  as  they 
are  to  their  colonial  friends. 
At  the  present  Exhibition,  owing  to  the  suggestion  of  the  Council  of 
the  Royal  Horticultural  Society,  fresh  fruits  are  shown  from  nearly 
every  part  of  the  British  Empire.  Thanks  to  the  Colonial  Market 
established  in  connection  with  the  Exhibition,  oranges,  lemons  and 
grapes  are  shown  from  the  Australian  Colonies ;  oranges  of  several 
kinds  from  Natal,  fresh  cocoa-nuts  from  the  west  coast  of  Africa,  pine- 
apples from  Antigua,  bananas  from  Jamaica,  naseberries  (Achras 
sapota),  Avocado  pears,  papaws,  bread-fruit  and  limes  from  British 
1  Abstract  of  a  paper  read  at  a  Conference  held  at  the  Colonial  and  Indian 
Exhibition.   Mr.  W.  T.  Thiselton  Dyer,  F.E.S.,  C.M.G.,  in  the  chair.   From  the 
Gardeners'  Chronicle,  July  24. 
