1 1  o  Proximate  Analysis  of  Plants.      { '^"'AS'ir^o!''™' 
pepsins  shown,  which  I  have  found  to  possess  considerable  digestive 
activity,  although  inferior  in  this  respect  to  the  pepsin  of  the  pig.  One 
of  the  specimens  is  unique  of  its  kind,  viz.:  pepsin  from  a  human 
stomach,  which  I  need  hardly  say  is  not  intended  for  medicinal  use. 
In  the  stomach  of  the  river  crayfish  is  found  a  plentiful  supply  of  a 
yellowish-brown,  feebly  acid  juice,  which  possesses  an  energetic  fer- 
menting power  and  rapidly  dissolves  fibrin,  but  the  addition  of  a  few 
drops  of  a  dilute  hydrochloric  acid  solution  stops  the  action.  Also,  a 
somewhat  similar  ferment  to  pepsin,  discovered  by  Fick  and  Murisier 
in  the  stomachs  of  frogs,  pikes  and  trout,  differs  from  it  (pepsin)  in 
being  more  active  at  a  low  temperature,  as  at  20°F.,  while  it  loses  its 
digestive  power  at  the  temperature  of  the,  blood  (96°  to  gS^F.) — 
Phar.  "Jour,  and  Trans. ^  Feb.  21,  1880,  p.  662. 
A  METHOD  for  the  PROXIMATE  ANALYSIS  of  PLANTS. 
By  Henry  B,  Parsons.^ 
At  the  request  of  my  friend  and  former  instructor.  Prof.  Albert  B.  Prescott,  of 
the  University  of  Michigan,  I  have  prepared  the  following  scheme  for  the  analysis 
of  plants.  This  method  will  appear  in  substance  in  his  new  "  Proximate  Organic 
Analysis,''  now  nearly  completed. 
The  plan  submitted  is  the  outgrowth  of  a  quite  varied  experience  in  the  proxi- 
mate analysis  of  plants;  no  claim  to  originality  is  made,  the  sole  aim  being  to 
arrange  in  one  simple  scheme  those  methods  best  suited  to  insure  accuracy. 
It  must  be  premised  that  no  one  method  is  applicable  in  all  cases,  and  that  the 
operator  will  so  modify  and  adapt  the  proposed  processes  as  to  best  attain  the  truths 
he  seeks.  If  the  present  scheme  shall  serve  merely  as  an  example,  to  be  improved 
upon  as  discoveries  multiply,  it  will  at  least  have  served  to  stimulate  to  the  more 
thorough  study,  this  side  the  Atlantic,  of  a  much  neglected,  yet  very  important, 
branch  of  analysis.  The  American  student,  when  first  entering  upon  the  study  of 
plant  analysis,  is  perplexed  and  disheartened,  owing  to  the  lack  of  any  elementary 
treatise  in  which  he  may  find  directions  for  the  quantitative  estimation  of  the  vari- 
ous plant  constituents.  The  works  of  Rochleder  and  Wittstein,  while  giving  most 
valuable  assistance  in  the  investigation  of  special  constituents  and  their  separation 
from  large  quautities  of  the  crude  herb,  still  fail  to  give  clear  and  practicable  direc- 
tions for  the  quantitative  estimation  of  each  constituent.  Von  Mueller's  latest 
enlarged  edition  of  Wittstein's  "Plant  Analysis"  gives  a  scheme,  most  excellent  in 
many  respects,  yet  cumbered  with  tiresome  methods  of  extraction  and  manipulation, 
which  serve  to  unnecessarily  lengthen  the  time  required  for  making  the  analyses 
without  increasing  the  accuracy  of  results  obtained. 
Too  many  American  analyses  of  plants  have  been  summarized  thus :  "  The  plant 
contains  gum,  resin,  tannin,  a  volatile  oil  and  a  peculiar  bitter  principle,  to  which 
may  be  ascribed  its  medicinal  activity."  The  foreign  journals  bring  occasionally 
1  Reprint  from  "American  Chemical  Journal,"  vol.  I,  No.  6.    Communicated  by  the  author. 
