Am.  Jour.  Pharm.  \ 
December,  1914.  J 
Belladonna  and  Hyoscyamus. 
533 
ecologic  and  physiologic  investigations  have  been  carried  out  with  a 
number  of  medicinal  plants,  for  the  most  part  these  studies  have  not 
been  made  with  the  object  in  view  of  securing  vegetable  drugs  of 
uniform  maximum  medicinal  values. 
The  Alternating  Annual  and  Biennial  Habit. 
In  connection  with  the  cultivation  of  Hyoscyamus  I  have  given 
some  attention  to  the  constancy  of  the  various  forms  under  observa- 
Fig.  i. — Hyoscyamus  niger,  biennial.    Portion  of  a  plot  showing  rosette  character  of  the  leaves 
and  their  long  petioles. 
tion,  to  determine  the  presence  or  absence  of  the  alternating  annual 
and  biennial  habit.  Before  giving  the  results  of  my  own  experiments 
along  this  line  I  will  briefly  discuss  the  phenomenon. 
De  Vries  states  that  in  plants  which  possess  the  alternating  annual 
and  biennial  habit  the  biennial  species  which  presents  the  character 
of  occurring  partly  in  annual  and  partly  in  biennial  specimens  must  1 
possess  the  capacity  of  growing  as  annuals  in  a  semi-latent  condi- 
tion, and  that  this  capacity  does  not  seem  to  be  universal,  but  to  be 
