56  Preparation  of  Thyroid  Extract.       { ^"'.b^uaJy  ^m™" 
In  conclusion,  the  author  desires  to  express  his  indebtedness  to 
Dr.  F.  B.  Power  for  having  suggested  this  research,  and  for  the  kind 
assistance  he  has  afforded  throughout  the  course  of  the  work. 
THE  PREPARATION  OF  THYROID  EXTRACT  FOR 
THERAPEUTIC  PURPOSES. 
By  S.  p.  Beebe,  Ph.D.,  M.D. 
During  the  last  ten  years  there  has  been  a  marked  increase  in  the 
interest  shown  toward  the  physiology  of  the  internal  secretions, 
and  the  therapeutic  value  of  organ  extracts  has  been  the  subject 
of  much  debate.  The  thyroid  gland  has  been  the  centre  of  much 
of  this  discussion  and  its  usefulness  as  a  therapeutic  agent  in  other 
conditions  than  those  of  the  classical  myxoedema  has  been  demon- 
strated so  thoroughly  that  the  demand  for  a  standard  preparation 
may  no  longer  be  ignored.  The  manufacturers  at  the  present  time 
supply  a  variety  of  thyroid  products  prepared  by  different  methods, 
and  undoubtedly  of  differing  therapeutic  effects.  The  terminology 
shows  great  confusion  and  the  precise  nature  of  the  substance  that  is 
provided  is  generally  not  known.  For  instance,  the  term  iodothyrine 
which  was  used  by  Baumann  ^  to  describe  the  substance  which  he 
obtained  by  hydrolyzing  thyroid  glands  with  ten  per  cent,  sulphuric 
acid.  This  substance  was  found  to  make  up  2-5  per  cent,  of  the 
glands  by  weight,  it  was  insoluble  in  acids,  soluble  in  alcohol  and 
alkalies,  contained  9.3  per  cent,  iodine,  and  from  the  experiments 
of  Roos  it  was  thought  .to  represent  all  the  physiological  activity  of 
the  gland.  The  same  term,  thyreoiodin,"  was  used  by  Roos  ^  to 
indicate  "  the  alcoholic  precipitate  of  a  glycerin  extract  of  the  well- 
pulverized  gland  dried  at  body  temperature."  In  Merck's  index  for 
1907  iodothyrine  is  the  name  given  to  "  milk  sugar  trituration  of  the 
active  constituent  of  the  thyroid  gland,  15  grains  of  which  contain 
1/200  grains  of  iodine."  In  some  instances  supposed  thyroid 
preparations  have  been  found  to  consist  of  meat  proteids  impreg- 
nated with  potassium  iodide,  or  a  poor  quality  of  gland  has  been 
enriched  by  the  addition  of  inorganic  iodine. 
The  experience  of  clinicians  confirms  the  belief  that  the  commer- 
cial preparations  are  not  uniform  and  that  they  are  at  times  entirely 
inactive.    Analyses  of  many  preparations  now  on  the  market  have 
