128 
Bacterial  versus  Vegetable  Toxins.     { ^fX"  m™' 
both  of  vegetable  and  animal  origin,  with  similar  products  elaborated 
by  bacteria  may  not  be  without  interest. 
It  is  only  comparatively  recently  that  the  existence  of  poisonous 
proteids  or  toxalbumins  has  been  recognized.  The  idea  that  a  proteid 
can  produce  dangerous  or  even  fatal  symptoms  or  act  in  any  way 
except  as  a  food  dates  only  from  1884,  but,  according  to  Cushny,  most 
of  the  animal  poisons  are  now  believed  to  be  of  proteid  nature,  and 
the  toxins  formed  by  microorganisms  of  disease  are  almost  certainly 
of  the  same  class. 
The  most  important  toxins  or  toxalbumins  of  the  vegetable  king- 
dom are  ricin,  ahrin,  and  crotin.  The  two  latter  are  obtained  respec- 
tively from  the  seeds  of  Abrus  precatorius  (jequirity)  and  C  rot  on 
Tiglium,  but  they  closely  resemble  ricin,  and  it  will  only  be  necessary 
here  to  refer  at  any  length  to  this  last-named  substance. 
Ricin  is  an  intensely  poisonous  phytoalbuminose,  which  may  be 
obtained  from  castor-oil  seeds  after  the  removal  of  the  oil.  It  occurs 
only  in  the  endosperm  and  embryo,  where  it  is  present  to  the  .extent 
of  2.8  to  3  per  cent.,  and  may  be  obtained  from  fresh  decorticated  and 
strongly  expressed  seed  by  percolation  with  a  10  per  cent,  saline 
solution  in  which  it  is  soluble.  The  percolate  is  filtered  and  saturated 
at  200  to  220  C.  with  magnesium  sulphate,  and  the  resulting  white 
precipitate  separated  from  the  crystallized  salts  by  dialysis.  This 
preparation  is  not  pure  ricin,  and  probably  contains  a  large  proportion 
of  albumins.  As  thus  obtained,  ricin  is  a  white,  odorless,  strongly 
toxic,  ash-yielding  powder,  insoluble  in  alcohol,  ether,  and  chloroform. 
The  chemical  nature  of  ricin  appears  to  be  analogous  to  that 
usually  ascribed  at  the  present  time  to  the  bacterial  toxins  and  fer- 
ments and  the  name  toxalbumin,  originally  suggested  by  KobeTt  and 
Stillmark,  who  first  investigated  the  substance,  is  abandoned.  Ricin 
differs  in  a  marked  manner  from  the  bacterial  toxins  and  snake 
venoms  by  its  relative  stability  towards  the  natural  fluids  and  fer- 
ments of  the  alimentary  tract.  For  this  reason  it  appears  to  be 
absorbed  by  the  intact  alimentary  tract,  and  thus  may  act  as  a  poison 
when  administered  by  the  mouth.  The  action  of  ricin  is,  however, 
much  less  powerful  in  the  stomach  than  when  injected  hypodermi- 
cally.  The  toxicity  of  the  substance  is  enormous,  and  it  may  certainly 
be  regarded  as  among  the  most  powerful  vegetable  poisons  when 
injected  directly  into  the  blood. 
According  to  Ehrlich,  1 -2000th  grain  per  2  pounds  body  weight  is 
fatal;  1  Gm.  (1543  grains)  subcutaneously  is  sufficient  to  kill  one 
