230  The  Pharmaceutical  Chemist.       { Am\J?i!r' ^rm' 
medium  in  which  they  act.  The  decomposition  of  hydrogen  per- 
oxide by  catalase,  which  reaction  may  be  used  for  the  quantitative 
determination  of  this  enzyme  in  the  blood  or  liver,  or  the  similar  de- 
composition by  colloidal  solution  of  platinum,  both  proceed  more 
rapidly  in  a  slightly  alkaline  medium.  The  presence  of  a  trace  of 
hydrocyanic  acid  acts  as  a  distinct  poison,  and  inhibits  the  activity 
both  of  enzymes  and  colloidal  solutions,  though  there  are  some 
exceptions  to  this  rule.  What  is  the  chemical  reason  back  of  these 
resemblances  between  substances  that  seem  otherwise  so  dissimilar? 
One  of  the  scourges  of  humanity  in  Eastern  Asia,  the  Philip- 
pines, Borneo,  Sumatra,  and  the  Straits  Settlement  has  been  a  dis- 
ease known  as  beri-beri.  This  through  long  and  laborious  investiga- 
tions was  found  to  be  connected  with  the  type  of  food  used,  being 
especially  prevalent  where  polished  rice  was  the  main  article  of  diet. 
It  was  found  that  a  very  remarkable  and  rapid  improvement  in  the 
condition  of  those  afflicted  wTith  this  disease  could  be  produced  by 
extracts  from  the  husks  and  polishings  removed  from  rice.  Con- 
tinued investigation  has  led  to  recognition  of  certain  bodies  called 
"  vitamines  "  present  not  only  in  the  pericarp  of  rice  but  also  in  other 
grains,  in  yeast,  and  in  a  number  of  different  plants.  The  name  has 
been  given  because  it  is  known  that  these  substances  are  related  to 
the  amines  and  are  so  intimately  associated  with  vital  processes. 
They  are  present  in  only  exceedingly  minute  amounts  and  yet  their 
effect  is  very  great.  To  the  presence  or  absence  of  the  same  com- 
pounds has  been  traced  the  disease  quite  prevalent  in  our  own 
southern  states,  known  as  "  pellagra." 
We  are  just  beginning  to  understand  that  these  vitamines,  which 
all  these  years  we  have  taken  into  our  systems  with  our  daily  food, 
have  in  some  way  a  tremendous  effect  upon  our  health,  but  how 
widely  they  are  distributed  or  what  their  chemical  constitution  is  and 
how  they  may  differ  as  derived  from  different  sources,  and  why 
they  are  so  necessary  to  our  healthful  existence,  still  remains  almost 
a  complete  mystery.  Few,  if  any,  greater  fields  for  chemical  in- 
vestigation of  medicinal  substances  exist  at  present  than  that  of  the 
vitamines. 
Some  400  years  ago  Paracelsus  founded  what  came  to  be  known 
as  the  School  of  Iatrochemistry,  on  the  assumption  that  the  human 
body  was  made  up  of  chemical  substances  and  that  illness  was 
caused  by  chemical  changes  in  the  organs  and  juices  of  the  body, 
and  that  to  cure  these  ills  chemical  compounds  must  be  found  that 
