160  Advances  in  Pharmacy.  { Am^™k  P^Y9m' 
with  starch,  casein,  butter  or  lard,  and  salts,  to  such  an  extent  that 
50  per  cent,  of  the  caloric  value  of  the  diet  is  silll  derived  from  the 
carrots,  will  produce  normal  growth  and  reproduction  in  albino  rats. 
Carrots  as  an  exclusive  diet,  except  for  the  addition  of  chlorine, 
calcium,  phosphorus,  sodium,  may  support  animals  in  apparently 
good  health  for  as  long  as  sixteen  weeks.  The  animals  on  such  a 
diet  maintain  and  very  often  increase  their  body  weight.  It  was 
demonstrated  that  carrots  contain  an  unusually  large  amount  of  both 
the  water-soluble  and  fat-soluble  vitamins.  They  believe  that  ordi- 
nary methods  of  cooking  do  not  materially  injure  the  nutritive  value 
of  carrots-,  certainly  not  when  used  as  part  of  a  mixed  diet.  They 
are  convinced  that  a  considerable  portion  of  the  caloric  value  of  the 
food  is  lost  when  the  water  used  in  cooking  is  rejected. — Jour. 
Biological  Chemistry,  Baltimore,  vol.  36,  1918,  249. 
Determination  of  Citral. — According  to  Parker  and  Hiltner  in 
making  determinations  for  citral  by  the  latter's  colorimetric  method 
with  metaphenylenediamine  hydrochloride  it  will  happen  at  times 
that  lemon  and  orange  oils  and  extracts  give  blue  or  green  colors  in 
place  of  yellow,  which  makes  the  use  of  this  method  more  or  less 
restricted.  Investigation  showed  that  this  was  due  to  oxidation  of 
some  constituent  of  the  citrus  oil,  and  experiments  tended  to  show 
that  the  addition  of  a  certain  amount  of  oxalic  acid  to  the  original 
Hiltner  reagent  would  be  a  most  practical  way  of  preventing  such 
blue  coloration.  The  reagent  as  modified  by  them  is  made  by  dis- 
solving 1  gram  of  the  metaphenylenediamine  hydrochloride  and  1 
gram  of  crystallized  oxalic  acid,  each  in  45  mils  of  80  per  cent, 
alcohol;  the  two  solutions  are  then  mixed  and  the  volume  brought 
up  to  100  mils  with  80  per  cent,  alcohol.  This  solution  is  then 
shaken  up  with  three  grams  of  fuller's  earth  and  filtered.  They 
give  detailed  information  as  to  the  use  of  this  colorimetric  method 
and  the  necessary  calculations. — /.  Ind.  and  Eng.  Chem.,  vol.  10, 
1918,  608,  through  The  Analyst,  Nov.,  1918. 
The  Output  of  Platinum. — In  conjunction  with  the  usual  uses 
to  which  this  valuable  metal  is  put,  namely  electrical  appliances, 
crucibles,  etc.,  the  requirements  were  greatly  augmented  during  the 
war  on  account  of  the  increased  needs  for  internal  combustion 
engines  for  airplanes,  automobiles,  tanks  and  motor  boats,  the 
manufacture  of  fuming  sulphuric  acid,  for  which  the  metal  is  em- 
