Am.  Jo0r.  Pharm. 
Not.  1, 1871. 
\      Water  Air-pump  and  its  Uses. 
501 
been  much  used  medicinally,  called  in  Spanish,  dog  killer,  big  fruit 
and  little  fruit.  The  dog  killer  is  the  only  true  officinal  cundurango, 
and  is  easily  distinguished  from  all  the  other  varieties,  by  the  fact 
that  when  cut  transversely,  the  bark  of  the  vine  is  full  of  small  red 
crystals,  which  are  resinous  and  shining  in  cells.  All  these  plants 
belong  to  the  Asclepiadese  family.  The  flower,  the  leaf  and  the  pod, 
with  the  seed  and  silk  fibres  of  the  true  "  mata  perro  "  or  dog  killer, 
look  almost  precisely  like  those  of  our  own  milkweed. 
The  cundurango  is  a  tropical  climbing  milkweed,  seeking  the  lofti- 
est trees  in  the  cinchona  region,  and  the  testimonials  about  it  are 
very  high  as  an  alterative  for  syphilitic  affections,  &c. 
In  haste,  your  friend, 
Dan.  C.  Robbins. 
ON  THE  WATER  AIR-PUMP  AND  ITS  USES. 
By  F.  a.  Wolff  &  Sons,  of  Heilbronn.* 
The  water  air-pump,  as  constructed  by  the  au- 
thors, consists  mainly  of  metal.  It  differs  also  from 
the  one  described  on  page  402  of  this  volume,  in 
the  admittance  of  the  water  from  the  top,  and  in 
making  the  connection  with  the  vessel  to  be  ex- 
hausted at  the  side.  The  laboratories  being  mostly 
on  the  ground  floor,  and  a  well  of  sufficient  depth 
frequently  not  at  command,  the  pump  itself  may  be 
placed  in  an  upper  story,  while  the  vacuo-meter, 
the  cock  for  the  water  supply,  and  a  piece  of  glass 
tube,  inserted  in  the  leaden  discharge-pipe,  may  be 
placed  in  the  laboratory,  the  only  inconvenience 
resulting  from  such  an  arrangement  being  the  in- 
creased length  of  two  or  three  pipes.  The  action 
of  this  air-pump  is  at  first  slow,  until  the  falling 
water  has  displaced  the  air  entirely  from  the  dis- 
charge-pipe, when  it  rapidly  increases. 
The  cut  represents  the  air-pump  in  one-tenth  of 
its  natural  size.  With  the  barometer  at  750  mm. 
and  a  bore  of  the  discharge-pipe  of  8  mm., a  rarifica- 
tion  of  the  air  was  obtained  corresponding  to  the 
Fig.  1. 
30 
*  Reprint  from  N.  Jahrbuch  fiir  Pharmacie,  communicated  by  the  authors, 
and  condensed  by  the  editor. 
