ON  THE  RESINS  AND  AQUEOUS  EXTRACT  OP  JALAP.  487 
minutes  intervened  in  receiving  answers  even  from  the  remotest 
points.  No  doubt  every  thing  had  been  pre-arranged,  so  that, 
at  each  point,  a  person  was  ready  at  the  precise  moment. 
ON  THE  RESINS  AND  AQUEOUS  EXTRACT  OF  JALAP. 
By  John  C.  Long. 
(An  Inaugural  Essaj.) 
The  plant  (Ipomea  jalapa)  has  been  so  fully  described  in  every 
systematic  treatise  upon  Materia  Medica,  since  Dr.  J.  R.  Coxe, 
formerly  Professor  of  Materia  Medica  in  the  University  of  Penn- 
sylvania, decided  authoritatively  the  question  relating  to  the 
origin  of  the  plant  furnishing  the  jalaps  of  commerce,  that  here 
a  detailed  account  is  deemed  entirely  unnecessary.  In  com- 
pliance with  the  expressed  wish  of  Dr.  R.  P.  Thomas,  our  worthy 
Professor  of  Materia  Medica,  when  lecturing  on  Jalap,  that 
some  member  of  the  class  would  examine  and  determine  une- 
quivocally whether  the  aqueous  extract  of  jalap,  deprived  of 
the  resins,  was  possessed  of  any  purgative  properties,"  I  have 
made  the  following  experiments. 
A  summary  of  the  experiments  of  Gerber,  Henry  and  other 
chemists  equally  distinguished,  is  here  given,  that  the  experi- 
ments I  have  instituted  may  be  more  intelligible: 
G-erhers  Analysis. 
Hard  resin  7-8 
Soft  resin  3-2 
Slightly  acrid  extractive  17-9 
Gummy  extractive  144 
Coloring  matter  8-2 
Uncryst.  sugar  1'9 
Gum  with  some  salts  15-6 
Bassorin,  starch  9-2 
Vegetable  albumen  4-7 
Water  4- 
Salts  of  lime 
Magnesia  and  potassa  13-1 
Henry's  Analysis, 
Resin 
Extractive 
Starch 
Woody  fibre 
Jalap 
12 
15 
19 
54 
100 
Analysis  of  the  Resins, 
Hard  resin  70 
Soft  resin  30 
Jalap 
100-0 
Jalap 
100 
