Ambecuri92iarm'  \  Advances  in  Photographic  Procedures.  843 
•  This  may  be  done  by  fixing  a  year's  work  in  a  retail  drug  store 
as  a  definite  number  of  hours  and  placing  an  arbitrary  value  for  the 
time  in  terms  of  UNITS.  Relative  values  may  then  be  given,  as 
seem  necessary  and  advisable,  for  pharmaceutical  experience  gained 
elsewhere.  Moreover,  such  a  system  of  crediting  practical  exper- 
ience provides  a  uniform  and  satisfactory  method  for  crediting  prac- 
tical experience  which  may  be  acquired  through  a  few  hours'  phar- 
maceutical work  in  a  pharmacy  each  day,  or  week,  while  the  pros- 
pective pharmacist  is  attending  high  school. 
RECENT  ADVANCES  IN  PHOTOGRAPHIC  PROCEDURES. 
By  Henry  Leffmann,  M.  D. 
Lecturer  on  Research,  Philadelphia  College  of  Pharmacy  and 
Science. 
Several  interesting  advances  in  photography  have  been  made 
during  the  current  year.  Perhaps  the  most  striking  is  the  discovery 
by  Liippo-Cramer,  of  Munich,  that  some  coal-tar  colors  will  desen- 
sitize to  a  considerable  extent  without  materially  affecting  the  latent 
image,  so  that  after  exposure  a  plate  can  be  immersed  for  a  brief 
period  in  a  solution  of  the  color  and  then  developed  in  a  much 
brighter  light  than  would  be  otherwise  applicable.  The  color  that  has 
been  found  most  satisfactory  is  phenosafranin,  a  red  dye  freely 
soluble  in  water.  This  is  used  in  dilute  solution  (0.5  gram  to  1000 
cc.)  the  plate  being  immersed  in  it  for  about  two  minutes,  rinsed, 
and  developed.  Ordinary  plates  may  be  developed  by  a  feeble  white 
light;  panchromatic  plates  by  a  red  light.  The  procedure  has  been 
found  satisfactory  for  autochromes.  The  red  tint  imparted  to  the 
plate  may  be  removed  by  washing,  but  in  the  case  of  autochromes 
the  oxidation  which  is  employed  after  the  first  development  removes 
the  color.  A.  &  L.  Lumiere  and  Seyewetz,  the  active  French  investi- 
gators in  this  field,  made  extensive  trials  of  other  materials,  espe- 
cially coal-tar  colors,  but  found  none  as  satisfactory  as  phenosafra- 
nin. Curiously,  it  was  found  that  apomorphia  hydrochloride  has  a 
desensitizing  action,  but  this  is,  of  course,  of  no  practical  importance. 
Solutions  of  phenosafranin  in  water  are  now  on  the  market  under 
trade  names.   The  French  investigators  just  noted  found  that  auran- 
