Amko0vU""i87h8arin"}  Botanical  Characters  of  Officinal  Plants.  533 
during  the  life  of  a  plant  is  the  change  of  the  nature  and  properties  of 
the  active  principle  according  to  the  time  at  which  the  plant  is  analyzed, 
and  according  to  the  organ  which  is  examined.  This  indicates  the 
necessity  of  having  a  specified  time — a  balsamic  period,  as  the  ancient 
writers  have  it — for  collecting  every  plant  and  every  part  thereof. 
We  will  not  here  consider  the  influence  of  the  soil  on  the  chemical 
composition  of  officinal  plants.  This  influence  certainly  exists,  but 
its  significance  has  undoubtedly  been  overestimated  ;  generally  it  only 
regulates  the  quantity  of  water  absorbed  by  the  plants.  If  the  plant  is 
of  an  aromatic  nature,  moist  soil  and  rain  will  cause  it  to  be  less  active. 
In  my  opinion,  the  influence  of  hybridizing  and  variation  is  of  much 
more  moment.  It  is  very  probable  that  a  natural  or  artificially-pro- 
duced variety  will  exhibit  a  more  or  less  marked  difference  from  the 
parent  type  of  which  it  arose.  This  is  only  a  consequence  of  the 
principles  of  transmutation  exemplified  by  our  fruit  trees  and  legumin- 
ous plants. 
From  these  observations  it  follows  that  to  form  a  limit  of  compari- 
son between  plants,  their  active  constituents  must  be  taken  as  founda- 
tion, and  not  their  properties.  This  necessitates  the  entire  discarding 
of  all  officinal  plants  whose  composition  is  not  satisfactorily  established, 
especially  the  exotics,  whose  properties  are  even  sometimes  known  merely 
from  descriptions.  When  chemistry  shall  have  made  more  advancement, 
when  vegetable  physiology  shall  have  explained  the  office  of  every  active 
substance,  then  the  principles  of  Linnaeus  will  become  more  universal 
and  its  exceptions  reduced  to  their  actual  value.  The  more  or  less 
diluted  state  of  the  active  substances,  and  the  presence  or  absence  of 
certain  anatomical  elements,  have  already  shown  analogies  where  they 
<lid  not  appear  to  exist.  If,  therefore,  the  exceptions  which  were  incom- 
prehensible to  DeCandolle  are  viewed  from  this  standpoint  they  are 
easily  explained.  Potatoes, like  other  solanaceae,  contain  solania ;  cherry- 
laurel  is  both  chemically  and  botanically  closely  allied  to  the  peach  and 
other  amygdaleae.  There  is  not  so  great  a  difference,  as  has  been 
shown  by  Endlicher  and  Guibourt,  between  the  properties  of  colocynth 
and  the  more  edible  fruits  of  the  same  order,  like  melons  and  pump- 
kins, only  that  in  the  cultivated  species  the  active  principle  is  more 
diluted  by  an  excess  of  starch  and  sugar.  Similar  is  the  relation  of  the 
sweet-potato  and  jalap  ;  here  the  influence  of  cultivation  is  clearly 
demonstrated,  and  to  what  extent  this  influence  may  alter  plants  is 
