620  Properties  and  Uses  of  Formaldehyde.  {XvemberS" 
formaldehyde  over  such  solutions  as  chromic  acid  and  mercuric 
chloride  or  even  absolute  alcohol.  Dr.  Eccles,  writing  to  the  British 
Medical  Journal,  has  stated  that,  whilst  the  last-named  reagents 
required  a  period  of  time  ranging  from  four  or  five  to  fourteen  days, 
and  the  tissues  either  became  brittle  and  unequally  hardened  or  the 
staining  was  interfered  with,  those  sections  treated  with  formalde- 
hyde were  sufficiently  hardened  in  three  days,  did  not  become 
brittle  and  stained  well,  the  cells  retaining  their  original  shape. 
A  Solution  of  Formal- 
dehyde Containing 
Effects  Produced. 
i  part  in  125,000  parts     .  . 
Kills  anthrax  bacilli. 
<  < 
Prevents  the  development  of  typhus  bacilli,  etc. 
(£            ^2  OOO 
<< 
Preserves  milk  for  several  days. 
{<  25>°°° 
(< 
Forms  a  useful  injection  in  leucorrhcea,  etc. 
20,000 
<  < 
Preserves  wines,  weak  alcoholic  liquids  and  beer, 
also  milk  for  several  weeks. 
4, 000 
«« 
Recommended  for  moistening  paper  used  to  cover 
jam,  etc. 
3,200 
For  rinsing  dairy  vessels,  etc. 
2,500 
<  < 
Destroys  the  most  resistant  micro-organism  in 
one  hour. 
2,000 
For  rinsing  casks  and  vessels  intended  for  liquids 
liable  to  fermentation. 
500 
For  the  irrigation  of  catheters,  etc.,  and  as  a 
mouth-wash. 
"  250  to  200 
a 
A  general  disinfectant  solution  for  washing  hands, 
instruments,  etc.,  in  surgery,  spraying  in  sick- 
rooms and  as  a  deodorant. 
"  160  to  100 
For  hardening  microscopic  tissues,  which  should 
be  immersed  for  a  considerable  time  to  give  the 
best  results. 
"  100 
( t 
In  lupus,  psoriasis  and  skin  diseases. 
"    50  to  25 
it 
Sterilizes  surgical  catgut,  silk,  etc.,  by  steeping. 
25 
( t 
For  quickly  hardening  and  preserving  for  micro- 
scopical sections  ;  longer  immersion  in  a  weaker 
solution  gives  better  results. 
"  10 
For  hardening  very  firm  tissues  \   in  pathological 
5 
"■}■'■■ 
"         firm  tissues         I  and  histological 
"  2, 
4U   J  . 
"          soft      "            J  work. 
The  foregoing  table  gives  the  purposes  for  which  formaldehyde 
has  been  employed,  and  the  proportions  recommended.    Two  and 
