436  Soap  as  a  Hygienic  Material.  {Am"sSt.r;Sarm" 
SOAP  AS  A  HYGIENIC  MATERIAL. 
By  Oscar  Liebreich,  M.D. 
The  general  conception  has  heretofore  been  that  the  secretion  col- 
lecting on  the  surface  of  the  skin,  "  die  Hautschmiere,"  originates  in 
the  sweat  and  also  in  the  sebaceous  glands,  and  that  the  mixture  of 
dried  sweat  and  sebum  covers  the  skin  as  "  uncleanness.''  I  have 
shown,  however,  in  my  investigation  with  lanolin  that  the  secretion  of 
cholesterin  fat,  hitherto  unknown  in  the  human  organism,  takes  place 
direct  from  the  tissues  containing  keratin.  The  epidermis  and  also 
the  epidermis  of  the  hair  can  directly  secrete  fatty  material.  Ac- 
cording to  the  earlier  views,  it  was  assumed  that  no  formation  of  fat 
took  place  in  the  epidermis.  One  imagined  the  keratin  structures, 
epidermis,  hair,  nails  as  properly  only  consisting  of  resisting  keratin. 
We  now  know  that  to  the  tissue  itself  fat  comes  which  is  not  prepared 
by  the  glands,  but  which  is  formed  within  the  tissue  itself  That 
under  pathological  conditions  an  excessive  secretion  of  the  sebaceous 
glands  takes  place  has  been  proved  by  Dr.  Lassar. 
The  secretion  may,  moreover,  attain  very  considerable  dimensions 
— e,  g.,  in  the  case  of  wool.  In  the  spines  of  the  hedge-hog  the  epi- 
dermis excretes  a  considerable  quantity  of  fat,  whilst  the  sebaceous 
follicles  belonging  to  them  are  starved. 
How  large  the  amount  of  fatty  contents  of  the  horny  tissues  may 
be  up  to  the  present  nothing  definite  is  known.  Apparently  there 
may  be  great  oscillations.  But  the  important  point  in  respect  of  hy- 
giene is  the  fact  that  cholesterin  or  some  analogous  fat  is  always  pres- 
ent in  the  horny  tissues,  although  often  in  small  quantities. 
In  the  question  of  cleansing  of  the  skin  in  a  hygienic  sense,  the 
above  described  condition  of  the  skin  is  to  me  naturally  of  the  greatest 
significance.  The  skin  should  undergo  cleansing  without  the  chemi- 
cal, and  still  more  the  physiological,  properties  suffering  any  change 
thereby.  The  skin  should  remain  intact.  If  it  were  simply  a  mat- 
ter of  cleansing  a  keratin  covering  of  the  products  that  are  deposited 
on  it,  the  use  of  rather  sharp  cleansing  material  would  not  so  much 
matter;  the  surface  might  be  slightly  cauterized  without  injury  to  the 
lower  layers.  But  if  we  make  use  of  sharp  material  the  fat  is  with- 
drawn from  the  horny  tissue  of  the  hair,  the  epidermis ;  the  epider- 
mis is  destroyed — at  any  rate,  rendered  more  absorbent ;  and  the 
lower  layers,  the  stratum  lucidum  and  granulosum,  and  farther  in  the 
cells,  are  given  up  to  destructive  action. 
