92  Notes  on  Some  Saps  and  Secretions.  {^FebrSy* 
Pharm. 
1895. 
(1)  Gums. 
(2)  Resins. 
(3)  Oleo-resins. 
(4)  Elastics  and  gums. 
The  first  would  include  ail  gums,  wholly  or  partially  soluble  in 
water,  whether  of  the  Acacia  or  Tragacanth  kind, 
The  second  would  include  resins  more  or  less  soluble  in  alcohol, 
such  as  copals,  mastics  and  gum  resins,  like  asafcetida  and  ammo- 
niacum. 
The  third  would  include  turpentine,  wood  oil  and  balsams. 
The  fourth  would  contain  India-rubber,  balata  and  gutta-percha, 
with  substances  of  a  similar  character. 
A  resin  is  entirely  soluble  in  alcohol,  but  insoluble  in  water.  A 
gum  resin  is  intermediate  in  character  between  a  gum  and  a  resin; 
that  is  to  say,  it  is  partly  soluble  in  water  and  partly  soluble  in 
alcohol. 
A  kino  is  the  astringent  inspissated  sap  of  a  tree. 
The  resins  may  be  divided  into  four  groups: 
(1)  Solid  or  dry  resins. 
(2)  Turpentines. 
(3)  Balsams. 
(4)  Soft  resins. 
Perhaps  it  is  better  to  arrange  the  products  alphabetically  under 
their  botanic  names. 
Abies  balsamea,  Marshall;  Abies  balsamifera,  Michaux ;  Pnuts 
balsam ea,  Lin. 
Canada  balsam  is  an  oleo- resin  produced  from  the  stem  of  this 
tree  by  incision,  and  is  also  yielded  by  Pinus  Fraseri,  Pursh. 
It  is  of  a  pale  straw  color,  and  is  occasionally  used  medicinally, 
but  is  chiefly  employed  for  mounting  objects  for  the  microscope,  and 
as  a  fine  transparent  varnish  for  water-color  drawings,  which  does 
not  become  darker  with  time. 
Abies  cxcclsa,  Poiret ;  Pinus  picea,  Du  Roi. 
Pinus  Abies,  Lin.  The  resinous  exudation  of  the  Norway  spruce 
fir,  melted  and  strained,  furnishes  the  concrete  oleo-resin,  true  Bur- 
gun  ly  pitch,  the  Thus  or  Frankincense  of  the  London  Pharma- 
copce  a.  The  com  non  frankincense  or  American  Thus  is  from 
Pinus  palustrts,  Lambert;  Pinus  Tceda,  Lindl.  It  acts  as  a  counter- 
irritant,  and  is  applied  to  the  chest  in  chronic  pulmonary  complaints, 
