no 
Chlorophyl  Complexities. 
(Am.  Jour.  Phaxm. 
\     February,  1920. 
The  results  obtained  in  experiments  with  malt  wort  can  be 
used  to  explain  the  action  of  yeast  in  other  cases. 
In  the  use  of  yeast  for  bread-making  large  amounts  are  put  into 
the  dough,  and  the  fermentative  activity  is  of  primary  importance. 
Brewery  yeast  is  unsatisfactory  for  bread-making,  for  it  is  rapidly 
inactivated  at  high  temperatures  (35°  C.)  by  certain  yeast  poisons 
in  the  flour.  Such  yeast  grown  in  distillers'  wort  is  less  sensitive, 
and  can  be  used  by  bakers.  According  to  J.  L.  Baker  (191 7)  un- 
boiled distillers'  wort  contains  these  toxins  and  the  yeast  crops 
from  such  media  consist  only  of  cells  which  are  immune,  and  there- 
fore of  use  to  the  baker.  One  suspects,  however,  that  the  hops  in 
brewery  wort  play  a  part  in  making  the  yeast  sensitive  and  useless 
for  bread-making  on  a  large  scale.  This  case  is  of  interest  for  rates 
of  inactivation  come  into  prominence. 
Yeast  activity  takes  place  under  many  varied  conditions.  It  is 
only  by  referring  back  to  the  simple  constants  of  growth  and  fer- 
mentation, and  to  the  factors  which  influence  these  constants,  that 
the  results  can  be  interpreted  and  the  process  understood. 
References. 
J.  L.  Baker,  Tms  Journal,  36:  836,  191 7. 
A.  J.  Brown,  Chem.  Soc.  Trans.,  61:  369,  1892. 
A.  J.  Brown,  Ibid.,  87:  1395,  1905. 
H.  T.  Brown,  Ann.  Botany,  28:  197,  19 14. 
H.  Chick,  /.  Hygiene,  10:  237,  19 10. 
J.  C.  G.  Ledingham  and  W.  J.  Penfold,  Ibid.,  14:  242,  1914. 
A.  Slator,  Biochem.  J.,  7:  197,  1913. 
A.  Slator,  Ibid.,  12:  248,  1918. 
A.  L.  Stern,  Chem.  Soc.  Trans.,  79:  943,  1901. 
CHLOROPHYL  COMPLEXITIES.  ^ 
By  John  Uri  Lloyd,  Pharm.M., 
CINCINNATI,  OHIO. 
1876.  Every  one  has  noticed  the  gradual  change  in  color  which 
a  green  leaf  undergoes  as  it  arrives  at  maturity  and  passes  into  de- 
•cay.    The  green  color  is  mostly  caused  by  a  substance  named 
1  From  The  Eclectic  Med.  Jour.,  Jan.,  1920. 
