means  ot  one  of  the  by-products  in  the  economy  of  the  human  body 
the  use  of  which  would  be  far  more  commendable  on  account  of  its 
inexpensive  character  than  for  its  attractiveness.  This  fable  has 
never  been  substantiated,  and  I believe  that  its  origin  is  simply  to 
to  be  found  in  the  offensive  urinal  smell  developed  on  the  fermen- 
tation of  the  albuminous  matter  in  crude  rubber. 
d'he  methods  followed  by  the  native  collectors  for  the  coagula- 
tion of  the  ('astilloa  latex  vary  considerably  : 
1.  The  latex  is  washed  with  water,  but  just  as  often  this  is 
neglected,  and  then  treated  with  a decoction  of  the  crushed  stem 
of  the  moon-plant,  Calonyction  speciosum.  This,  according  to  Dr. 
Morris,  is  the  process  practised  in  British  Honduras. 
2.  The  latex  is  treated  with  the  juice  expressed  from  Ipomcea 
bona  nox  which  is  stated  to  be  highly  alkaline.-  (?) 
3.  The  latex  is  collected  in  shallow  holes  dug  in  the  ground  and 
mixed  with  a boiling  solution  of  soap  in  water.  This  process  is 
extensively  practised  in  the  Isthmus  of  Panama. 
5.  The  latex  is  treated  with  a solution  of  alum. 
These  various  methods  call  for  the  following  remarks: — Allot 
them  effect  the  so-called  coagulation  by  adding  to  the  latex  sub- 
stances— acids,  or  alkalies — capable  of  coagulating  the  albumen. 
In  other  words  there  is  no  such  thing  as  the  coagulation  of  the 
indiaruhher  itself.  What  takes  place  is  that  through  the  addition 
to  the  latex  of  either  an  acid,  or  faintly  alkaline  solution  the  albu- 
men, of  which  I have  shown  there  is  such  a large  amount  in  the 
Castilloa  latex,  is  coagulated  and  carries  down  with  it  the  rubber 
globules  suspended  in  the  latex.  If  the  latex  is  entirely  freed  from 
all  albuminous  matter  by  a carefully  conducted  series  of  washings 
it  may  still  be  diluted  with  water,  and  then  forms  a liquid  milky 
liquid  of  a somewhat  lighter  colour  than  the  original  latex,  but 
otherwise  indistinguisliable  from  it.  But  if  we  now  try  to  coagulate 
this  albumin-free  liquid  with  any  of  the  abov’enamed  coagulants 
we  hnd  that  the  rubber  remains  quite  uneffected,  no  coagulation 
taking  place.  Therefore,  whenever  we  coagulate  the  rubber,  we 
can  only  do  so  by  coagulating  it  in  conjunction  with  the  albumen 
present,  and  we  have  at  once  a product  possessing  all  the  irremedi- 
able drawbacks  which  above  we  discussed  at  some  length. 
On  the  plantation  at  Las  Cascadas,  Calonyction  speciosum  is 
very  common,  and  I ascertained  that  decoctions  prepared  from  it 
have  a strongly  acid  reaction.  Therefore,  coagulation  with  such  a 
decoction  is  simply  the  wellknown  coagulation  of  solutions  of  albu- 
men with  acids.  I have  not  been  able  to  discover  at  Las  Cascadas 
Ipomoea  bona  nox.  but  I very  much  doubt  the  highly  alkaline 
character  of  its  juice  which  it  is  almost  certain  to  possess  likewise  a 
distinctly  acid  reaction.  The  treatment  with  alum,  a process  due  to 
H.  A.  Strauss,  and  purchased  from  him  by  the  local  Government  of 
the  province  of  Pernambuco,  owes  its  coagulating  action  entirely  to 
the  strongly  acid  reaction  of  that  salt.  This  process  is  a bad  one 
from  every  point  of  view.  The  removal  of  the  alum  solution  from 
the  coagulated  rubber  is  physical  impossibility,  and  the  pernicious 
action  of  an  alum  solution  upon  the  diying  rubber  is  quite  sufficient 
