Am.  jour,  Pharm. )       Theories,  of  Blood-Coagulation  713 
is  ordinarily  the  case  in  the  coagulation  of  whole  blood,  shows  a 
marked  affinity  towards  a  new  amount  of  serozyme.  As  a  matter 
of  fact,  such  an  affinity  is  so  strong  that  it  causes  thrombin  to  at- 
tract and  to  possess  itself  of  serozyme  even  when  this  principle  is 
still  present  in  a  state  of  proserozyme.  Consequently,  finished  throm- 
bin acts  as  though  it  could  bring  about  a  remarkably  quick  conver- 
sion of  proserozyme  into  serozyme,  the  process  preliminary  to  the 
genesis  of  fresh  thrombin  being  thus  greatly  hastened.  The  con- 
sequence is  that,  when  thrombin  is  added  to  oxalated  plasma  which 
has  been  just  recalcified,  the  total  amount  of  thrombin  this  quantity 
of  plasma  is  apt  to  furnish  appears  much  more  rapidly  than  it  doe9 
when  the  same  plasma  is  allowed  to  clot  spontaneously  without  the 
stimulus  of  thrombin.  In  fact,  thrombin  itself  thus  accelerates  the 
formation  of  thrombin.  Owing  to  lack  of  time,  I  cannot  report  here 
in  detail  the  experiments  which  have  established  this  idea,  but  shall 
now  consider  briefly  some  of  the  views  held  by  certain  authors  and 
which  are  not  in  agreement  with  the  ideas  developed  above. 
As  is  well  known,  my  countryman,  the  physiologist  Nolf,  has 
adopted  the  rather  startling  theory  of  Wooldridge  according  to 
which,  instead  of  being  the  immediate  determining  factor  of  coagula- 
tion, thrombin  is  generated  as  a  consequence  of  the  coagulation  it- 
self. According  to  Nolf,  the  transformation  of  fibrinogen  into  fib- 
rin is  not  the  effect,  but  the  necessary  condition  of  the  appearance 
of  thrombin.  Many  of  the  data  which  I  have  recorded  above  ener- 
getically plead  against  such  a  conception.  '  For  example,  I  would 
only  recall  the  experiments  showing  the  production  of  thrombin  in 
fluids  altogether  devoid  of  fibrinogen,  and  thus  proving  unques- 
tionably that  fibrinogen  does  not  play  any  role  in  the  production  of 
the  coagulating  principle. 
One  important  point  has  been  and  still  is  controverted.  I  mean 
the  true  significance  of  the  lipoid  to  which  we  have  so  often  al- 
luded. Schmidt,  who  had  already  observed  the  accelerating  in- 
fluence on  coagulation,  exerted  by  alcoholic  extracts  of  tissues, 
believed  that  such  lipoids  rendered  easier  the  production  of  throm- 
bin, without  assuming,  as  I  do,  that  they  really  enter  into  its  con- 
stitution. One  of  the  most  distinguished  among  the  writers  who 
have  devoted  their  skill  to  the  study  of  coagulation,  Professor  . 
Howell,  especially  directed  his  attention  towards  the  fact  that  the 
lipoid  extracted,  for  example,  from  nervous  tissue,  is  capable  of 
