668 
Alkaloids  in  the  Human  Urine. 
Am.  Jour.  Pharm. 
Nov.,  1888. 
other  of  its  modifications,  meta-uropittin  and  uro-rubin,  and  is  partially 
altered  by  contact  with  the  oxygen  of  the  air.  It  contains  11  per  cent, 
of  nitrogen.  Its  alcoholic  solution  is  red,  and  gives  an  absorption- 
band  at  F. 
Uromelanin  has  the  composition  C36II43N7O10,  and  is  insoluble  in 
alcohol  or  ether,  but  dissolves  in  dilute  solutions  of  the  alkalis,  from 
which  it  is  precipitated  by  acids.  With  silver,  barium,  calcium,  lead, 
and  zinc  it  forms  basic  and  acid  salts.  The  silver  salt  has  the  com- 
position C36H40 AgNyOg.  Uromelanin  is  a  very  stable  substance ;  the 
quantity  excreted  by  an  adult  is  0"3  to  0"5  gram  per  day. 
Neither  urochrome  nor  any  of  the  other  products  can  be  obtained 
crystallized.  Urochrome  is  an  alkaloid,  the  function  of  Avhich  is  as 
yet  unknown.  The  products  of  its  decomposition  are  not  related  to 
the  coloring  matters  of  the  blood  or  of  the  bile. 
If  the  filtrate  from  the  urochrome  iron  precipitate  is  concentrated,  it 
yields  bulky  crystals  which  may  be  purified  by  recry stall  ization  from 
alcohol.  These  consist  of  an  alkaloid,  uro-iheohromine,  isomeric  with 
ordinary  theobromine.  It  sublimes  without  change,  forms  no  crystal- 
line precipitate  with  silver  nitrate,  and  displaces  acetic  acid  from  cupric 
acetate,  forming  an  insoluble  compound. 
Creatinine  is  also  present,  and  the  mother-liquor  from  the  creatinine 
contains  three  alkaloids.  Reducine,  C12II26N6O9  or  C6Hii]S'304,  forms 
a  barium  compound  which  is  almost  insoluble  in  alcohol.  Neutral  or 
acid  solutions  of  reducine  reduce  ferric,  cupric,  or  mercuric  salts  to 
ferrous,  cuprous,  or  mercurous  salts  respectively,  and  silver  salts  to 
metallic  silver.  Para-reducine  unites  with  zinc  oxide  to  form  a  com- 
pound, CgHgNgO-ZnO  or  C6H9ZnN302.  Aromine  could  not  be  isolated 
in  a  pure  condition.  When  heated,  it  gives  off  an  aromatic  odor  re- 
sembling that  obtained  from  tyrosine  under  similar  conditions. 
Toxicity  of  tlie  £xlialed  Air.— At  the  Soc.  de  Biologie  {Brit.  3[ed. 
Jbur.),  M.M.Brown-Sequard  and  d'Arisonval  reported  on  some  recent  experi- 
ments concerning  the  toxicity  of  the  air  exhaled  from  the  lungs  of  man  or 
of  mammals.  They  assert,  first,  that  the  air  exhaled  nearly  always  contains 
ammonia;  secondly,  this  air  contains  in  very  minute  quantities,  organic 
matter  which,  if  not  already  putrefied  on  leaving  the  broncho-pulmonary 
passages,  has  a  great  tendency  to  rapid  alteration,  even  at  a  low  tempera- 
ture ;  thirdly,  confined  air  charged  with  pulmonary  exhalations  is  extremely 
noxious,  even  when  containing  1  per  cent,  of  carbonic  acid,  with  a  corre- 
sponding diminution  of  oxygen. 
