214 
Medicinal  Manganese  Dioxid. 
/Am.  Jour.  Pnarm. 
\      May.  1903. 
"  Externally  it  is  of  black  color,  and  having  a  lustre  not  unlike  that 
of  pitch,  to  which  at  first  sight  it  bears  some  resemblance.  The 
fracture  is  black  and  glossy  and  very  slightly  porous.  The  powder 
is  of  a  pale  brown  hue." 
NATAL  ALOES. 
This  variety  of  aloes,  while  not  at  the  present  time  an  article  of 
commerce,  has  figured  so  extensively  in  the  pharmaceutic  literature 
of  comparative  recent  times  that  some  references  to  its  almost  phe- 
nomenal rise  and  fall  in  popular  favor  would  not  appear  out  of  place. 
According  to  the  Pharmacographia,2  the  first  aloes  was  exported 
from  Natal  in  1869.  From  this  date  the  amount  rapidly  increased 
for  several  years.  The  statistics,  quoted  by  the  same  authority,  are 
as  follows: 
1868.  1869.  1870.  1871.  1872. 
None  38  cwt.  646  cwt.  371  cwt.  501  cwt. 
Therapeutic  reports  on  this  variety  of  aloes  were  not  favorable, 
however,  and  its  popularity  waned  so  rapidly  that  in  1890  not  a 
single  person  in  the  neighborhood  of  Greytown  was  making  or 
gathering  aloes,  and  none  was  being  exported.37 
At  the  present  time  no  samples  of  this  variety  of  aloes  are  avail- 
able outside  of  museum  specimens.  Gehe  &  Co.,  in  answer  to  a  let- 
ter of  inquiry,  report  that  this  variety  oi  aloes,  ten  to  fifteen  years 
ago,  had  quite  an  extensive  sale,  being  the  kind  usually  supplied  to 
their  trade  when  "  hepatic  aloes  "  was  called  for.  They  have  not 
been  able  to  supply  this  particular  kind  of  "  hepatic  aloes "  for 
upward  of  ten  years. 
(  To  be  continued.) 
A  METHOD  FOR  THE  PREPARATION  OF  MEDICINAL 
MANGANESE  DIOXID. 
By  August  Gotthki,f,  Ph.D. 
The  object  of  the  following  work,  carried  out  at  the  instance  of 
Professor  Coblentz,  was  to  devise  a  method  for  the  preparation  of  a 
pure  manganese  oxid  of  approximately  constant  composition 
adapted  for  medicinal  use.  With  exception  of  the  method  adopted, 
all  other  methods  which  have  been  proposed  are  open  to  the  objec- 
tion of  being  either  beyond  the  means  of  the  average  pharmacist, 
or  they  yield  precipitates  which  are  exceedingly  difficult  to  purify, 
