Amjui°y  ri92]i arm' }    Astringencies  of  Red  and  Pale  Rose.  499 
thick  syrupy  residue ;  it  consisted  of  the  astringent  principle  and  the 
substance  which  others  have  called  "quercitrin."  Efforts  to  obtain 
the  "tannin"  in  a  porous  condition  were  unsuccessful  in  operating 
upon  this  quantity.  But  it  was  converted  into  scale  form  by  dissolv- 
ing in  alcohol  and  evaporating  with  heat  on  an  enameled  surface. 
Although  the  purification  was  not  an  entire  success,  the  material 
by  displaying  the  peculiar  properties  of  "the  tannin  of  red  rose"  in 
its  behavior  toward  reagents,  proved  its  identity  with  that  substance. 
Especially  was  this  fact  established  by  the  production  of  the  burr-like 
aggregates  when  the  solution  of  the  principle  was  treated,  hot  or 
cold,  with  diluted  mineral  acids. 
There  is  every  reason  to  believe  that  this  astringent  substance 
is  present  in  both  drugs,  but  in  very  much  smaller  quantity  in  Pale 
Rose,  perhaps  less  than  one  per  cent,  of  its  weight. 
As  it  is  becoming  more  and  more  evident  that  astringency  is  not 
a  characteristic"  of  any  one  substance,  no  more  than  the  property  of 
bitterness  is  indicative  of  any  single  material  or  group  of  them,  we 
question  the  desirability  of  continuing  to  apply  to  such  principles 
(other  than  gallotannic  acid)  the  names  "tannic  acid  and  tannin." 
Instead,  as  a  means  of  obviating  a  possibly  improper  terminology, 
the  suggestion  is  offered  that  such  plant  substances  may  well  be 
grouped  under  the  name  of  "astringents,"  with  a  prefix  to  indicate 
the  source ;  as  for  example :  qUercastringent,  rosastringent,  etc. ;  until 
they  are  chemically  classified,  and  even  then  a.  name  so  practical  as 
these  may  be  preferable  to  an  intricate  one  which  details  the  chem- 
ical structure  of  the  substance. 
Effect  of  Mildew  Upon  Red  Rose  and  Pale  Rose. 
■  i> 
Another  feature  of  the  paper  presented  in  1920  was  a  reference 
to  a  crystalline  principle  which  seemed  to  develop  under  the  influence 
of  mildew  growth  upon  an  unstrained  infusion  of  Red  Rose.  By 
means  of  an  ether  extraction  of  these  materials  this  substance  was 
obtained  in  fine  white  or  colorless  crystals,  but  in  very  small  amount. 
To  further  study  this  matter,  and  more  especially  this  time  to 
confirm  this  behavior,  about  500  grams  of  Red  Rose  were  exhausted 
with  ether  to  remove  any  pre-existent  ether  soluble  contents. 
This  treatment  revealed  the  presence  of  fatty  and  waxy  con- 
