478 
Deterioration  of  Artificial  Foods. 
/Am.  Jour.  Pharm 
X     October,  1901. 
must  be  given  primarily  to  the  ingredients  and  constituents  of  the 
various  artificial  foods. 
The  constituents  taken  collectively  may  be  divided  into  three 
general  classes,  *.  e. : 
(1)  Fats. 
(2)  Proteids. 
(3)  Carbohydrates. 
These  may  be  still  further  subdivided  according  to  their  origin, 
whether  it  be  animal  or  vegetable ;  the  carbohydrates  may  be 
soluble  or  insoluble,  that  is,  they  may  consist  of  sugars  or  dextrins, 
or  they  may  belong  to  the  group  of  starches. 
The  ingredients  furnishing  these  constituents  may  be  of  the  fol- 
lowing : 
Dried  milk,  flours  or  ground  cereals,  sugars  or  dextrins,  starches, 
desiccated  eggs  or  meat  extracts. 
The  deterioration  may  be  due  to  chemical  changes  involving  one 
or  more  of  these  constituents  or  may  be  due  to  physical  alterations 
brought  about  in  one  of  several  ways. 
The  principal  causes  involving  chemical  change  may  be  divided 
into  three  classes,  i.  e. 
(1)  Oxidation  of  the  fatty  matter,  resulting  in  what  is  commonly 
known  as  rancidity. 
(2)  Fermentative  changes,  which  generally  affect  the  carbohy- 
drates. 
(3)  Putrefactive  changes,  which  involve  the  proteid  or  albuminous 
matter. 
The  oxidation  of  the  fatty  matter  is  the  only  one  of  these 
changes  that  can  possibly  take  place  in  the  dry  product,  as  both 
putrefaction  and  fermentation  require  the  presence  of  a  certain 
amount  of  moisture  for  their  accomplishment. 
This  oxidation  as  it  is  called  may  be  of  bacterial  origin,  or  it 
may  be  due  simply  to  the  action  of  the  oxygen  in  the  atmosphere. 
The  latter  supposition  is  borne  out  by  the  fact  that  this  change 
occurs  in  dry  material  (or  material  containing  less  than  5  per 
cent,  of  moisture),  is  favored  by  access  of  air  and  retarded  by  pro- 
tection from  the  atmosphere. 
"Thorpe's  Dictionary  of  Chemistry  "  says  concerning  the  stabil- 
ity of  fixed  oils  and  fats  :  "  If  air  be  excluded  the  fixed  oils  may 
be  preserved  unchanged  for  a  lengthened  period ;  when  absolutely 
