406  Rhus  Glabra  and  Rhus  Typhina.      {h^tlZ*  *\llf' 
malic  and  gallic  acids.  W.  B.  Rogers  9  later  proved  that  the  malic 
acid  was  in  the  form  of  a  calcium  salt  and  outlined  a  method  for 
obtaining  it  in  crystalline  form.  In  1853  William  J.  Watson  10  made 
some  quantitative  studies  on  the  fruits  of  Rhus  glabra  and  showed 
that  the  amount  of  malic  acid  and  bi-malate  of  calcium  varied  in 
the  fruits  collected  at  different  months  in  the  same  year.  Fruits  col- 
lected in  the  latter  part  of  August  contained  0.50  per  cent,  of  malic 
acid  and  7.46  per  cent,  of  bi-malate  of  lime.  Specimens  collected 
late  in  September  gave  2.75  per  cent,  of  uncombined  malic  acid 
and  3.50  per  cent,  of  bi-malate  of  lime.  He  also  determined  quali- 
tatively the  presence  of  gallic  and  tannic  acids.    H.  K.  Bowman  11 
Name  of  drug 
Rhus  glabra  (old  drug)  
Rhus  glabra  (old  drug)  
Rhus  glabra  (whole  fruits)  
Rhus  glabra  (whole  fruits) .... 
Rhus  typhina  (whole  fruits) .  . 
Rhus  typhina  (whole  fruits) .  . 
Rhus  typhina  (drug  )  
Rhus  typhina  (drug  )  
later  showed  that  the  fruits  of  Rhus  glabra  contained  1.90  per  cent, 
of  tannic  acid.  John  Stenhouse  12  conducted  some  rather  interesting 
experiments  on  the  tannin  in  sumac  and  came  to  the  conclusion  that 
the  tannic  acid  in  sumac  was  related  to  that  found  in  allepo  and 
Chinese  galls.  Henry  Trimble  13  examined  all  parts  of  the  plants 
of  both  Rhus  glabra  and  Rhus  typhina  at  different  seasons  of  the 
year  and  found  that  the  berries  collected  in  September  contained 
less  tannin  than  those  collected  in  August.  Prof.  Trimble  14  also 
reported  on  the  amount  of  tannin  found  in  the  galls  which  were 
occasionally  formed  on  Rhus  glabra.  In  an  article  on  "  The  Chemi- 
cal Study  of  the  Seed  of  Rhus  glabra,"  Frankforter 15  and  Martin 
have  given  some  very  interesting  results  especially  on  the  nature 
of  the  fixed  oil  found  in  the  kernel  of  the  seeds. 
In  completing  this  portion  of  the  article  there  are  a  few  refer- 
ences to  the  published  work  on  the  coloring  matter  of  Rhus  glabra 
that  might  be  mentioned.  The  first  article  in  which  mention  is  made 
of  the  nature  of  this  principle  is  that  of  Watson  10  already  referred  to. 
He  considers  that  the  true  color  is  blue  and  that  it  is  changed  to  red 
Quantity  used 
grams 
grams 
grams 
grams 
grams 
grams 
grams 
grams 
No.  Cc. 
NaOH(V.  S) 
1  cc.  =  0.004749- 
NaOH 
48.2 
51.8 
434 
41.7 
66.2 
50.2 
72.1 
71.4 
The  percentage 
of  acid  in  the 
fruits  in  terms  of 
malic  acid 
7.506 
8.067 
6-759 
6.494 
IO.309 
7.818 
11.228 
II. 119 
