THE  AMERICAN 
JOURNAL  OF  P 
JULY,  jp, 
ALKALOID AL  ASSAY:  A  SIMPLE  GENERAL  METHOD 
Once  the  identity  of  a  drug  or  its  galenical  preparation  has  been 
established,  the  determination  of  at  least  its  total  alkaloids  presents 
no  more  difficulties  than  that  of  a  similar  amount  of  metallic  bases. 
The  concordance  of  results  obtained  may  be  favorably  compared 
with  data  relating  to  the  analysis  of  soils  or  foods — indeed,  com- 
parison with  those  of,  for  instance,  methyl  alcohol  in  grain  spirit,  or 
fusel  oil  in  beverages,  would  be  somewhat  invidious. 
Although  differing  widely  in  their  molecular  structure,  the  alka- 
loids have  many  properties  in  common,  peculiarly  adapting  them 
for  assay  by  general  methods ;  advantage  may  be  taken  of  the  simi- 
larity of  their  behavior  towards  certain  precipitating  agents  or  their 
properties  of  combining  with  the  stronger  acids  to  form  neutral 
salts.  So  far  the  consensus  of  opinion  favors  estimation  by  means 
of  this  latter  (basic)  property,  since  with  the  aid  of  delicate  indicators 
it  is  possible  to  determine  the  amount  of  a  free  alkaloid  within 
three- tenths  of  a  milligramme. 
Before  these  methods  can  be  applied,  however,  approximate 
purification  of  the  alkaloid  is  necessary.  Here,  again,  the  pre- 
eminence of  the  "  shaking  out  "  process  is  almost  universally  con- 
ceded ;  taking  advantage  of  the  fact  that  most  alkaloids  are 
insoluble  in  water  and  soluble  in  chloroform  or  ether,  and  that  their 
salts  exhibit  contra-distinctive  properties  towards  these  solvents,  the 
active  principles  can  be  transferred  from  one  solvent  to  the  other 
until  almost  the  whole  of  the  inert  matter  of  the  drug  is  eliminated. 
Simple  as  the  principle  is,  great  difficulties  are  met  with  in  its 
practical  application.    When  the  two  immiscible  liquids  are  thor- 
By  m.  H.  Webster. 
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