AmMa°rch,Xym"}        Manganese  Occurring  in  Plants.  147 
The  relation  between  camphene,  borneol,  and  camphor  is  shown  by 
the  following  formulae  : — 
,CH2— CH2  x  ,CH0  CH2 
C3H-C^-  7CMe.         C3H/C^  yCMe. 
'    X-CH  :  CH-X  xCH2-CH(OH)  x 
Camphene.  Borneol. 
C3H7-C^  yCMe. 
x  CHVCO  x 
Camphor. 
Borneol  bears  the  same  relation  to  camphene  that  terpineol  does  to 
dipentene. — Jour.  Chem.  Soc,  1886,  p.  70;  Annaleny  ccxxx,  p.  225-272. 
MANGANESE  OCCUKKING  IN  PLANTS. 
By  Professoe  Fluckigee. 
It  is  well  known  that  manganese  is  widely  spread  throughout  the 
vegetable  kingdom,  although  it  always  occurs  in  very  small  amount. 
No  doubt  there  are  certain  plants  provided  with  the  power  of  absorb- 
ing the  said  metal,  whilst  others  would  appear  to  be  unable  to  assimi- 
late manganese.  It  is  true  that  much  more  striking  facts  of  a  similar 
order  are  to  be  noticed  with  regard  to  iodine.  Among  marine  plants 
there  are  none  superior  to  the  Laminar iai,  which  are  so  well  known  as 
an  important  source  for  iodine,  or  at  least  were  so  for  a  long  time.  I 
have  ascertained  that  5  grams  of  Laminaria  Cloustoni  (or  L.  hyper- 
bored)  are  quite  sufficient  for  demonstrating  the  presence  of  iodine  in 
its  tissue.  The  drug  is  repeatedly  boiled  with  water,  the  decoction 
concentrated  to  a  few  c  cm.  and  mixed  with  alcohol  in  order  to  pre- 
cipitate the  mucilage.  From  the  filtrate  the  alcohol  is  to  be  distilled 
off,  when  the  residual  liquid,  on  addition  of  ferric  chloride,  yields 
undoubted  traces  of  iodine  to  bisulphide  of  carbon,  with  which  the 
mixture  is  to  be  vigorously  shaken.  Carrageen,  which  would  also  be 
available  in  considerable  quantities  for  manufacturing  iodine,  has  never 
been  resorted  to  for  that  purpose,  and  that  for  good  reasons.  Carra- 
geen is  not  able  to  take  up  iodine  from  the  water  of  the  ocean.  This 
may  likewise  be  demonstrated  by  the  experiment  just  mentioned;  if 
much  more  than  5  grams  of  carrageen  are  treated  in  the  same  way  as 
laminaria,  no  iodine  at  all  will  be  found.1 
1  See  also  Stanford's  exhaustive  papers  on  the  subject,  Pharm.  Journal,  xiii 
(1883)  ,  1019,  1037;  xiv  (1883  and' 1884),  353,  1051;  also  Wheeler,  Ibid.,  xii 
(1882),  642.   See  also  Amer.  Jour.  Phae.  (1882),  p.  124;  (1883),  pp.  612,  618; 
(1884)  ,  p.  582. 
