Am.  Jour.  Pharm. 
Nov.,  19 18. 
Diph  theria  A  n  titoxin . 
775 
According  to  Starke,  globulin  in  solution  is  an  alkali  or  acid 
albumin.86 
Carbonic  acid  precipitates  globulins  from  dilute  alkaline  solution 
and  dissolves  them  in  excess. 
The  serum  globulins  are  sensitive  to  reagents  and  easily  de- 
naturize,  thus  becoming  insoluble.  Heat,  alcohol,  and  ether  quickly 
precipitate  them.87  They  are  "  slowly  split  by  ferments  such  as 
pepsin.88 
Globulins  do  not  form  true  salts  with  metals.  The  globulins 
have  an  acid  nature  and  form  combinations  with  alkalies.  Histon, 
nuclein,  neucleohiston,  etc.,  are  said  to  precipitate  globulins.89 
.  Acetic  acid  (0.25  per  cent.)  precipitates  diphtheria  antitoxin.90 
Acetic  acid  also  precipitates  globulins. 
Admixed  substances  may  determine  the  solubility  of  the  globu- 
lins, as  a  globulin  preparation  soluble  in  water  can  become  insoluble 
in  water  by  purification,  hence  classifications  based  on  solubility 
must  be  tentative. 91 
According  to  Hammarsten,  "  a  sharp  line  cannot  be  drawn  be- 
tween the  albumins  and  the  globulins,  follows  from  the  fact  that  the 
albumins  can  be  converted  into  globulins."92  The  first  step  in  the 
transformation  of  albumin  into  globulin  is  the  formation  of  pseudo- 
globulin.  This  change  may  be  really  a  question  of  external  proper- 
ties of  the  albumin  rather  than  to  a  true  conversion  into  a  globulin, 
as  the  resulting  substance  does  not  contain  glycocoll,  which  is  be- 
lieved to  be  present  in  globulins. 
On  the  addition  of  colloidal  calcium  phosphate  and  kieselguhr 
to  diphtheria  antitoxic  serum,  the  ionized  salts  in  the  serum  cause 
a  precipitate,  but  the  antitoxic  value  of  the  serum  remains  the  same, 
showing  that  all  colloids  do  not  carry  down  antitoxin.93 
86  See  Physiol.  Abst.,  1918,  Vol.  3,  p.  100. 
87  Tebb,  M.  C,  Journ.  Physiol,  Vol.  30,  p.  25,  1904.  See  also  Chick,  H., 
and  Martin,  C.  J.,  Journ.  Physiol.,  45,  61,  1912. 
88  Umber,  F.,  Zeits.  f.  physiol.  Chem.,  Vol.  25,  p.  258,  1898. 
89  See  Osborne,  in  "  Abderhalden  Biochemisches  Handlexikon,"  Vol.  4, 
p.  84. 
90  Gibson,  R.  B.,  Journ.  Biol.  Chem.,  p.  169,  Vol.  1,  1905-06. 
91  For  methods  of  precipitation  see  Samuely,  in  Abderhalden's  "  Hand- 
buch  der  Biochem.  Arbeitsmethoden,"  Vol.  2,  p.  360;  Morawitz,  in  Oppen- 
heimer's  "  Handbuch  der  Biochemie,"  Vol.  2. 
92  Hammersten,  O.,  "Textbook  of  Physiol.  Chem.,"  7th  ed.,  transl.,  1912; 
p.  103  refers  to  Moll-Hofmeister's  "  Beitrage,"  Vols.  4  and  7. 
93  Mellanby. 
