542     MANUFACTURE  AND  PROPERTIES  OF  ANILINE  COLORS. 
three  years  of  age  ;  their  little  "  pearly  gems  "  appear  more  like 
a  miniature  array  of  mouldering  tomb-stones,  dilapidated,  jagged, 
and  broken ;  frequently  emitting  an  odor  so  foul  as  to  compel 
one  to  stand  at  a  respectable  distance  while  viewing  the  ruins. 
Look  also  into  the  mouth  of  an  adult  who  pays  no  attention  to 
the  cleanliness  of  his  teeth  ;  notice  the  discolored  remnants  of  a 
once  perfect  set  of  dentures  ;  see  the  huge  scales  of  calcareous 
deposit  encircling  the  necks  of  the  teeth,  or  nearly  investing 
their  entire  crowns ;  observe  the  tumid  condition  of  the  gums, 
and  how  the  filthy  calculus  has  forced  them  to  recede,  and  it  is 
no  wonder  they  recede  at  the  approach  of  such  an  offensive 
accumulation.  I  do  not  say  that  the  use  of  a  tooth-brush  and 
dentifrice  will  positively  insure  the  teeth  against  decay,  but  a 
habitual  cleansing  process  will  greatly  prolong  their  existence. 
I  have  heard  it  asserted  that  teeth  are  worn  out  by  being  cleansed. 
Even  were  this  so,  they  had  better  wear  out  than  rust  out,  or,  as 
the  old  saying  reads,  "die  clean  if  you  will  not  live  clean." 
But  this  is  not  apt  to  be  the  case.  I  have  seen  but  a  very  few 
persons  in  my  whole  life  whom  I  could  conceive  had  injured  their 
teeth  by  too  much  brushing,  but  have  seen  hundreds  upon  hun- 
dreds whose  teeth  were  going  to  utter  destruction  from  lack  of 
care  and  tidiness.  I  do  not  believe  in  straining  at  the  gnat  and 
swallowing  the  camel.  Cleanliness,  gentlemen,  cleanliness  is 
next  to  godliness.  Teeth  should  be  brushed  night  and  morning, 
particularly  at  night,  for  it  is  during  the  night  that  teeth  are 
most  ready  to  decay.  During  the  day,  the  movements  of  the 
tongue,  the  fresh  secretions  of  saliva,  and  the  act  of  mastication, 
all  tend,  in  a  measure,  to  preserve  the  teeth ;  but  during  the 
night,  little  or  no  saliva  is  secreted,  and  particles  of  food  filling 
their  interstices  being  so  long  subjected  to  a  moist  and  heated 
condition,  rapidly  ferment,  and  the  fluids  of  the  mouth  are  thus 
vitiated,  inducing  disease  and  decay. — Dental  Cosmos,  Philada., 
Aug.,  1866. 
THE  MANUFACTURE  AND  PROPERTIES  OF  ANILINE  COL- 
ORS,  AND  THE  BODIES  USED  IN  THEIR  PREPARATION* 
Memoir  presented  to  the  Societe  Industrielle  de  Mulhouse  at  the  meeting  of  May  31, 1865. 
By  MM.  Depoully,  Brothers. 
1.  Oils  used  in  making  Commercial  Aniline. — The  source 
