^°'o2t'!yim^'°' }       Furfuraldehyde  Color  Reaction.  507 
Some  of  the  substances  examined  gave  a  coloration  with  sulphuric 
acid  alone ;  the  tint  given  with  furfuraldehyde  also  varied  a  great 
deal ;  the  particulars  in  each  case  are  stated  in  a  lengthy  table.  The 
reaction  was  found  not  to  be  a  class  reaction.  The  substances  which 
give  a  color  are  as  follows  : — Acetal,  acetaldehyde,  ethyl  acetoacetate, 
acetone,  ethylene  glycol,  malic  acid,  alizarin,  amyl  nitrite,  anilidoacetic 
acid,  aniline,  anisaldehyde,  anthracene,  anthraquinone,  apomorphine, 
atropine,  l)enzaldehyde,  borneol,  catechol,  brucine,  quinic  acid,  choles- 
terin,  cinchonine,  codeine,  coniferin,  conine,  cumarin,  cyanuric  acid, 
cymene,  digitalin,  dimethylaniline,  dihydroxytartaric  acid,  diphenyl- 
amine,  gallic  acid,  Japan  camphor,  cresol,  Isevulinic  acid,  mesitylene, 
mesityl  oxide,  metaldehyde,  methyl  alcohol,  methylhydantoin,  methyl- 
aniline,  morphine,  naphthalene,  a-naphthol,  a-naphthascatol,  oenanth- 
aldehyde,  orcinol,  paraldehyde,  paraffin,  phenanthrene,  phenan- 
thraquinone,  phenol,  phenylhydrazine,  phloroglucinol,  phorone,  prop- 
aldehyde,  protocatechuic  acid,  pyrogallol,  resorcinol,  salicaldehyde, 
salicylic  acid,  scatol,  stearic  acid,  strychnine,  toluene,  thymol,  tyrosine, 
valeraldehyde,  vanillin,  vanillic  acid,  vaselin,  veratrine,  metaxylene, 
paraxylene,  cinnamaldehyde. 
The  substances  which  gave  no  color  are  as  follows : — Acetamide, 
acetanilide,  acetophenone,  alloxan,  alloxantin,  aspartic  acid,  benzo- 
nitril,  benzoic  acid,  succinic  acid,  hydrocyanic  acid,  pyruvic  acid, 
butyric  acid,  caffeine,  caproic  acid,  quinine,  chinoline,  quinone,  quin- 
oxaline,  chloral  hydrate,  chloroform,  citric  acid,  crotonic  acid,  cyan- 
amide,  dextrin,  metadinitrophenol,  dinitrotoluidine,  dulcitol,  acetic 
anhydride,  formamide,  fumaric  acid,  fermentation  lactic  acid,  glycerol, 
glycocine,  glycollic  acid,  glyoxal  hydrogen  sulphite,  uric  acid,  urea, 
hippuric  acid,  isatin,  leucine,  malic  acid,  maltose,  mandelic  acid, 
mannitol,  methylamine,  orthonaphthoxyindol,  metanitraniline,  ortho" 
nitrobenzaldehyde,  orthonitrobenzoic  acid,  orthonitrophenol,  ortho- 
nitrophenylpropionic  acid,  oxalic  acid,  ethyl  oxalate,  parabanic  acid, 
metaphenylenediamine,  phenylacetic  acid,  picrotoxin,  picric  acid, 
piperidine,  pyridine,  quinol,  mucic  acid.  Starch,  tannin,  tetroxyethyl- 
benzidine,  grape-sugar,  tartaric  acid,  tri methylamine,  urethane,  xyli- 
dine,  cinnamic  acid. 
The  spectroscopic  appearances  of  the  colors  obtained  differ  in  many 
cases ;  in  all  probability  the  products  are  therefore  different ;  particu- 
lars in  the  case  of  a  few  of  the  more  important  substances  are  given ; 
in  the  case  of  bile  there  is  a  band  between  D  and  E,  an<l  another  at 
