2 
Belladonna  and  Hyoscyamus. 
i  Am.  Jour.  Pharm. 
(    January,  1915. 
being  most  abundant  on  the  latter.  They  are  present  on  the  seedlings 
of  a  few  months'  growth,  as  well  as  on  the  mature  plants.  They 
may  attain  a  total  length  of  as  much  as  five  millimetres,  and  a  width 
at*  the  base  of  from  seventy-five  to  eighty  microns.  They  are  richly 
protoplasmic  when  in  the  living  condition,  and  they  have  thin,  non- 
lignified  walls,  the  walls  being  from  one  to  two  and  one-half  microns 
thick.  The  stalks  (i.e.,  the  cells  below  the  branching)  vary  in  length 
from  one  hundred  to  twenty-seven  hundred  microns,  and  usually 
consist  of  from  one  to  five  cells,  occasionally  more.  The  branches,  of 
which  there  may  be  one  or  two,  rarely  three,  consist  of  lateral  pro- 
longations of  cells  from  the  main  hair  or  of  from  one  to  ten  or  more 
distinct  cells  arising  from  the  joints  or  sides  of  cells  in  the  main 
axis.  The  apices  of  the  branching  hair  are  obtuse  or  rounded, 
occasionally  enlarged  and  spherical.  The  latter  form  does  not 
appear  to  contain  oil,  but  is  richly  protoplasmic. 
In  Belladonna  branching  hairs  were  observed  on  each  of  a  large 
number  of  plants  examined,  the  selection  of  plants  representing  some 
from  each  lot  wintered  by  different  methods.  The  branching  hairs 
on  Belladonna  are  mostly  found  on  the  young  shoots,  as  the  plant 
begins  growth  in  the  spring  and  they  are  located  on  the  same  part 
of  the  leaf  as  found  in  Hyoscyamus.  The  greatest  length  of  a 
branching  hair  observed  in  Belladonna  was  thirty- four  hundred 
microns,  and  the  greatest  width  at  the  base  seventy-eight  microns. 
The  form  of  branch  represented  by  the  lateral  prolongation  of  a  cell 
is  only  occasionally  found  in  Belladonna  and  the  length  of  the  indi- 
vidual cell  is  usually  somewhat  less  than  in  Hyoscyamus.  In  other 
respects  the  branching  hairs  of  Belladonna  resemble  those  of  Hyo- 
scyamus. The  branching  hairs  in  Belladonna  are  not  confined  to 
those  plants  which  are  especially  hairy. 
The  young,  rapidly-growing  leaves  of  Nicotiana  tabacum  and 
N.  repanda  also'  possess  branching  hairs  which  closely  resemble  those 
of  Belladonna  and  Hyoscyamus,  and  which  are  quite  different  from 
any  which  have  heretofore  been  described. 
The  broken- joint  portions  of  these  branching  hairs  I  have 
observed  in  commercial  Hyoscyamus  powdered  in  my  laboratory. 
They  are  more  abundant  in  drug  which  represents  basal  first-year 
leaves  than  in  flowering  tops.  In  either  case  their  detection  is  diffi- 
cult, due  to  the  thin,  delicate  structure  of  the  hairs,  which  results 
in  their  breaking  up  more  or  less  completely.    The  branching  hairs 
