112  Toxic  Constituent  of  Poison  Ivy.  -jAl 
Table  VII. 
Comparison  of  Alkaloidal  Content  of  Belladonna  Leaves,  Varying  in  Size  from 
the  Smallest  to  the  Largest,  each  Sample  being  a  Collective 
Picking  from  the  Entire  Row. 
Row  No.  i. 
Row  No.  2. 
Sample 
Alkaloids  (per 
cent.) 
Sample 
Alkaloids  (per 
cent.) 
i  (smallest) 
2 
3 
4 
5 
6 
7 
8  (largest) 
0.62I 
O.706 
O.664 
O.766 
O.598 
O.406 
O .  I IO 
O.  Il6 
I  (smallest) 
2 
3 
4 
5 
6 
7 
8  (largest) 
0.598 
O.700 
O.669 
0 .804 
O.605 
0.523 
0.324 
0.212 
rapidly  picked  owing  to  their  size.  It  is  economically  out  of  the 
question  to  pick  such  leaves  as  constitute  samples  1  and  2,  while 
samples  3  to  6  should  represent  the  best  leaves  available  for  all  pur- 
poses, appearance  as  well  as  strength,  and  from  both  the  medicinal 
and  commercial  standpoint. 
THE  VOLATILE  NATURE  OF  THE  TOXIC 
CONSTITUENT  OF  POISON  IVY. 
By  Charles  E.  Bessey. 
There  is  a  pretty  general  agreement  among  medical  men  that 
the  active  poisonous  principle  in  Poison  Ivy  (Rhus  radicans  L., 
Toxicodendron  radicans  (L.)  Kuntze)  is  a  non- volatile  oil,  and 
that  as  a  consequence  poisoning  without  contact  is  impossible.  Yet 
there  are  many  assertions  to  the  contrary  by  those  who  have  been 
victims  of  this  poisonous  principle.  I  have  heard  persons  assert 
that  they  had  been  poisoned  when  walking  or  driving  by  the  Poison 
Ivy.  I  have  always  maintained  a  feeling  of  considerable  doubt  in 
regard  to  such  cases,  for  it  is  obviously  difficult  to  prove  lack  of 
contact. 
However,  I  myself  once  suffered  from  a  severe  case  of  poisoning 
without  contact,  as  I  reported  a  few  years. ago  in  a  paper  entitled 
"A  Preliminary  Account  of  the  Plants  of  Nebraska  which  are 
