6o 
Preparation  of  Thyroid  Extract. 
{Am.  Jour.  Pharm. 
February,  1911. 
teid,  which  he  names  nucleoproteid,  free  from  iodine  and  without 
functional  activity.  In  my  laboratory  we  have  used  various  methods 
of  fractioning  the  extracts  from  different  types  and  species  of  thy- 
roid gland  in  the  hope  of  obtaining  a  series  of  proteids  varying 
somewhat  in  composition  and  physiological  activity.  Such  a  series 
we  have  obtained,  but,  contrary  to  Oswald,  in  no  case  have  we 
found  nucleoproteid  or  other  proteid  free  from  iodine  nor  have  we 
found  any  of  the  primary  or  secondary  albumoses  obtained  on  diges- 
tion to  be  free  from  iodine.  When  tryptic  digestion,  or  acid  hydro- 
lysis is  carried  beyond  the  biuret  stage  a  variety  of  fragments  con- 
taining iodine  are  obtained.  Even  in  extracts  from  perfectly  fresh 
glands  the  filtrates  obtained  after  removing  the  heat  coagulable 
proteids  contain  iodized  peptones,  and  if  the  glands  are  not  fresh 
the  amount  of  these  peptone-like  substances  is  much  increased. 
It  is  evident,  then,  that  when  the  whole  thyroid  gland  is  ground, 
dried,  and  pulverized  for  therapeutic  use  that  a  variety  of  iodine- 
containing  proteid  and  non-proteid  substances  is  included.  Are 
they  all  necessary  or  equally  valuable  physiologically,  and  may  it  not 
be  that  some  of  them  are  actually  jiarmful?  In  an  endeavor  to 
answer  these  questions  and  also  to  determine  the  best  method  of 
preparing  the  physiologically  active  portions  for  therapeutic  use 
we  have  made  many  experiments.  I  shall  not  describe  in  detail  the 
many  methods  employed  to  fractionate  the  proteids,  but  will  outline 
the  procedure  which  we  have  finally  hit  upon  as  the  simplest  and 
most  effective  for  preparing  thyroid  extract  for  therapeutic  use.  We 
have  used  glands  from  sheep,  beef,  and  pig.  In  so  far  as  we  can 
judge  by  the  gross  appearance  only  normal  glands  are  selected  and 
this  I  think  is  a  valuable  point,  as  heretofore  only  sheep  glands  have 
been  used  therapeutically  and  it  became  evident  very  early  in  this 
work  that  sheep  from  certain  regions  always  had  goitrous  glands 
poor  in  iodine.  Moreover,  it  was  these  glands  that  the  abattoir 
preferred  to  furnish  since  they  were  sold  by  the  pound  and  the 
glands  necessary  for  a  pound  were  more  easily  obtained  if  goitres 
were  used.  I  have  seen  such  glands  in  the  course  of  preparation 
into  thyroid  extract  at  two  commercial  laboratories.  Such  glands 
are  rich  in  proteid  of  the  thyreoglobulin  type  but  very  poor  in  iodine. 
Obviously  here  is  an  adequate  source  for  much  of  the  variation  of 
thyroid  preparations.  The  normal  glands  are  obtained  in  as  fresh 
a  condition  as  possible  and  are  kept  from  autolysis  by  freezing. 
They  are  ground  to  a  fine  pulp  and  extracted  with  three  to  four 
