.« 
ORGANIC  MATTER  OF  HUMAN  BREATH,  ETC.  255 
ance  of  mucus  in  those  complaints,  by  which  the  fine  solid  par- 
ticles of  the  breath  were  entangled. 
In  two  cases  of  whooping  cough  it  was  also  deficient,  but  as 
they  were  both  children,  the  lack  of  organic  matter  may  have 
been  due  to  their  age. 
In  cases  of  consumption,  also,  the  total  ammonia  was  less 
than  in  health ;  but  in  one  case  of  this  disease  associated  with 
Bright's  disease  a  large  amount  of  organic  matter  was  given  off, 
a  portion  of  it  due  to  urea. 
In  kidney  diseases  the  largest  amount  of  organic  matter  of  all 
kinds  was  found  in  the  breath.  The  ammonia  in  one  case  of 
Bright's  disease  was  1*8  milligrammes  in  100  minims  of  fluid, 
and  urea  was  largely  present.  Perhaps  this  fact  might  be  taken 
as  an  indication  of  the  need  of  measures  directed  to  increase  the 
activity  of  other  excretory  organs. 
In  one  case  of  ozoena  or  offensive  breath  the  total  quantity  of 
ammonia  obtained  was  greater  than  in  any  healthy  subject,  but 
the  excess  was  chiefly  due  to  organic  matter. 
One  convalescent  case  of  fever  was  examined,  and  the  total 
ammonia  was  found  to  be  deficient. 
The  air  of  a  crowded  railway  carriage,  after  fifteen  minutes 
occupation,  was  also  tested  by  this  method,  and  in  about  2  cubic 
feet  0*3  milligrammes  of  ammonia  and  3  milligrammes  of  organic 
matter  were  found. 
With  reference  to  the  presence  of  organic  matter  in  the  at- 
mosphere, it  was  pointed  out  that  the  subject  was  in  no  way  a 
novel  one,  and  that  it  had,  during  the  last  thirty  years,  been  very 
fully  investigated  by  many  observers,  more  especially  by 
Schwann,  Dasch,  Schroeder,  Helmholtz,  Van  den  Broeck,  Pas- 
teur and  Pouchet,  but  it  was  shown  that  it  is  to  Dr.  Angus 
Smith  that  we  owe  the  discovery  of  the  readiness  with  which 
living  organisms  are  formed  in  the  condensed  breath  of  crowded 
meetings,  and  the  determination  of  the  actual  quantity  of  organic 
matter  in  the  air  of  different  localities. 
Mr.  Dancer's  calculation  of  the  number  of  spores  contained  in 
the  air  was  noticed,  but  a  source  of  error  was  pointed  out  in  the 
readiness  with  which  organisms  are  developed  in  suitable  fluids, 
