406 
Cutaneous  Absorption* 
(  Am.  Jour.  Pharh. 
I     Sept.  1|  1872. 
lively  color ;  thus  affording  clear  proof  of  the  absorption  of  iodide  of 
potassium  through  the  skin,  the  only  way  it  could  have  entered  the 
system.  Besides,  if  it  had  entered  by  pulmonary  passages,  it  would 
have  been  eliminated  immediately  after  the  bath.  These  first  experi- 
ments, then,  prove  the  fact  of  cutaneous  absorption. 
In  a  second  series  I  sought  to  determine  to  what  temperature  the 
air,  mixed  with  medicamental  vapor,  must  be  raised,  in  order  to  the 
absorption  taking  place. 
A  very  sensitive  thermometer  was  applied  to  the  breast  of  the  sub- 
ject, and  the  temperature  of  the  bath  varied  in  the  series  of  experi- 
ments from  30°  to  38°,  the  time  being,  as  before,  thirty  minutes.  I 
only  found  the  absorption  take  place  when  the  temperature  was  38° 
(or  one  degree  above  the  temperature  of  the  body).  Indeed,  the  se- 
baceous matter  in  the  cells  of  the  epidermis  only  commences  to  dis- 
solve at  38°  when  the  skin  is  really  wet ;  it  is  then  that  imbibition 
takes  place,  and  consequently  absorption.  The  iodide  of  potassium^ 
conveyed  mechanically  by  the  vapor,  penetrates  the  epidermis,  whence 
it  passes  into  the  capillary  blood  system  and  the  other  organs. 
Thus  we  understand  how  absorption  does  not  generally  take  place 
in  a  water-bath.  Owing  to  the  density  ol  the  water,  and  its  great 
specific  heat,  the  temperature  of  such  baths  is  usually  not  raised  be- 
yond 30°  to  33°.  Dr.  Homolle  remained  in  a  bath  at  34°  or  35°  \ 
would  he  have  been  able  to  bear  38°  or  39°  ?  Besides,  the  liquid 
layer  touching  the  skin  is  not  constantly  renewed,  as  in  the  vapor- 
bath. 
I  succeeded,  however,  in  obtaining  the  cutaneous  absorption  at  a 
temperature  under  that  of  the  body,  in  the  following  way : — 
The  subject  had  first  a  simple  vapor-bath,  to  destroy  the  sebaceous 
matter  ;  his  skin  was  washed  and  carefully  dried,  and  he  was  replaced 
immediately  in  the  cage,  where  he  was  exposed  to  the  vapor  of  iodide 
of  potassium  for  thirty  minutes,  the  temperature  of  the  bath  varying, 
in  several  experiments  of  this  kind,  from  34°  to  36°.  Two  hours 
after  a  bath  at  34°  the  coloration  of  the  urine  was  slightly  rose  ;  after 
a  bath  at  36°  it  was  much  more  distinct. 
M.  Colin  has  described  an  experiment  in  which  he  allowed  water 
charged  with  cyanide  of  potassium  to  fall  for  five  hours'  time  on  a 
horse's  back.  This  caused  the  death  of  the  animal ;  the  sebaceous 
matter  having  been  destroyed  through  percussion,  and  cutaneous  ab- 
sorption taking  place. 
