452 
The  Use  of  Drugs  in  Disease. 
Am.  Jour.  Pharm. 
July,  1920. 
amino  acids  are  found  in  every  cell  of  the  human  body  but  are  par- 
ticularly abundant  in  hair  and  nails,  skin  and  mucous  membrane. 
Every  tissue  that  is  exposed  to  infection  by  parasites,  to  an  unusual 
degree,  contains  more  than  those  not  so  exposed.  They,  with 
cystin  and  cy stein,  that  contain  oxidizable  sulphur,  are,  strange  to 
say,  the  first  of  the  amino  acids  released  by  trypsin  in  the  bacteria 
laden  intestine.  There  they  produce  the  well-known  antiseptic 
substances  named  and  particularly  carbolic  acid.  There  the  danger 
of  having  the  cell-foods — the  amino  acids — stolen  by  saprophytes 
and  parasites  is  greatest  for  these  organisms  subsist  and  fatten,  as 
do  the  cells,  on  these  amino  acids.  The  oxidation  of  cystin,  by 
bacteria,  produces  sulphurous  acid  an  antiseptic  about  as  powerful 
as  carbolic  or  benzoic  acids  which  it  fortifies.  It  seems  as  if  nature 
had  set  a  trap  for  the  parasites  by  which  they  injure  themselves  as  a 
cheese-set  trap  catches  mice.  Meats,  fish,  eggs,  milk,  glutin,  and 
the  like,  all  contain  an  abundance  of  these  bacteria-inhibitors  that 
only  act  when  being  digested  or  putrified.  The  odor  of  skatol  in 
putrid  food  is  evidence  of  the  fact  that  the  bacteria  are,  by  their 
depradations,  producing  antiseptic  substances  to  inhibit  their  activ- 
ity. The  tyrosin  is  abundant  in  melanins,  the  pigments  of  the 
negro's  rete  mucosum,  the  choroid  coat  of  the  eye,  and  in  the  hair. 
With  the  approach  of  old  age  the  hair  turns  gray,  the  nails  brittle, 
and  the  eye -sight  dim  because  of  a  shortage  of  tyrosin  and  its  oxidizing 
enzyme,  tyrosinase.  Skin  affections  also  increase  as  melanin  dimin- 
ishes. The  black  skin  of  the  negro  accompanies  his  relative  immunity 
from  yellow  fever,  malaria  and  trypanosome  disease  as  compared 
with  the  lack  of  immunity  in  white  men.  Darwin  has  pointed  out 
that  certain  skin  diseases  of  animals  attack  only  unpigmented  ones, 
leaving  the  pigmented  untouched,  while  piebald  animals  are  attacked 
only  on  white  spots.  The  shortage  of  tyrosin  seems  to  be  responsible. 
Millions  of  years  ago  the  phenylalanin  and  tyrosin  of  plants  was 
buried  in  the  ground  with  the  plants  that  produced  them.  We  now 
dig  them  up  as  coal  and  the  aromatic  radicals  of  these  amino  acids 
constitute  the  antiseptic  substances  of  coal  tar.  Our  beautiful  anilin 
colors  and  our  many  new  synthetic  remedies  have  come  from  these. 
Their  antiseptic  power  have  preserved  them  for  all  these  years  from 
the  depradations  and  ravages  of  time.  We,  too,  like  coal,  derive 
our  antiseptic  radicals  from  plants  as  no  animal  seems  to  possess 
the  power  to  produce  them,  in  spite  of  the  fact  that  none  can  live 
without  them. 
