202 
Coagulation  of  the  Blood. 
J  Am.  Jour.  Pharm. 
[       April,  1892. 
to  contain  calcium,  but  no  phosphoric  acid,  and  further,  in  the 
present  research,  it  is  shown  that  injection  of  disodium  phosphate 
into  the  circulation  of  a  living  animal  is  not  followed  by  throm- 
bosis. 
Arthus  and  Pages  {Arch,  de  Physiol.,  1890,  No.  4)  found  that 
blood  coagulation  may  be  entirely  prevented  if,  immediately  on 
being  shed,  the  blood  is  mixed  with  small  quantities  of  substances, 
like  oxalates  or  fluorides,  which  precipitate  calcium  salts  as  very 
insoluble  compounds.  On  adding  to  the  plasma  obtained  from  this 
blood  a  slight  excess  of  calcium  chloride,  coagulation  immediately 
ensues.  Fibrin  ferment  is,  however,  essential  for  the  process;  and 
the  action  of  this  agent  is  considered  to  be  the  bringing  together  of 
fibrinogen  and  the  calcium  compound,  and  thus  the  formation  of 
fibrin.  In  this,  they  draw  a  close  analogy  between  fibrin  formation 
and  the  formation  of  casein  in  milk  under  the  influence  of  the  ren- 
net ferment.  Green  attempted  to  answer  the  question  :  Does  the 
fibrin  ferment  exist  as  zymogene  in  the  plasma,  and  is  such  zymogene 
converted  into  the  ferment  by  the  action  of  the  calcium  salt  ?  He 
was  unable  to  find  a  positive  answer  ;  and  therefore  considered  that 
the  calcium  acts  in  assisting  the  ferment  much  as  hydrochloric  acid 
in  the  gastric  juice  favors  the  activity  of  pepsin.  This  question  is 
again  taken  up  in  the  present  investigation,  and  it  was  found  possi- 
ble to  prepare  from  plasma  (such  as  oxalate  plasma  which  contains 
no  ferment)  a  globulin  which  has  no  fibrinoplastic  properties,  which, 
however,  after  contact  with  calcium  chloride,  is  converted  into  the 
ferment.  The  zymogene  yields  an  ash  containing  little  or  no  cal- 
cium, whilst  the  ferment  is  rich  in  calcium.  The  material  in  ques- 
tion arises  from  the  formed  elements  of  the  blood,  and  is  identical 
with  what  is  called  cell-globulin  by  Halliburton. 
Fibrin,  moreover,  is  a  calcium  compound,  and  the  main  action  of 
the  ferment  appears  to  be  to  transfer  the  calcium  to  the  fibrinogen. 
Granting  this  hypothesis,  it  is  possible  to  explain  several  facts 
hitherto  but  little  understood  in  connection  with  blood  coagulation, 
and  to  reconcile  certain  conflicting  theories.  The  action  of  oxalates 
in  hindering  coagulation  is  explained  on  the  supposition  that  the 
precipitate  of  calcium  oxalate,  on  account  of  its  insolubility,  is  not 
available  for  the  conversion  of  zymogene  into  ferment.  The  action 
of  neutral  salts  in  restraining  clotting  is  explained  on  the  assump- 
tion that  the  ferment  is  a  globulin,  and  although  the  amount  of  salt 
