88 
Coffee- Leaf  Tea. 
Am.  Jour.  Pharm. 
Feb.,  1892. 
sulphate,  sodium  sulphate  and  phosphate),  starch  and  sugar  had  no 
such  action,  but  certain  products  of  proteolytic  activity  (albumose, 
amphopeptone  and  antipeptone)  act  like  the  salts  just  enumerated. 
All  the  materials  that  act  in  this  way  increase  the  alkalinity  of  the 
digesting  medium  ;  minute  doses  of  sodium  hydroxide  act  in  a  pre- 
cisely similar  way,  and  the  proposition  is  advanced  that  the  whole 
of  the  phenomena  are  simply  dependent  on  the  reaction.  Increase 
of  alkalinity  protects  the  ferment.  It  was  found  that  increase  of 
acidity  (trypsin  will  act  'in  an  acid  medium  if  salicylic  acid  be 
employed)  acts  in  exactly  the  opposite  way ;  in  an  acid  medium* 
33-35°  is  the  optimum  temperature;  400  hinders,  and  450  destroys, 
the  action  of  the  ferment. 
Pepsin  was  then  investigated,  and  it  was  found  that  acidity  acts 
towards  this  ferment  precisely  like  alkalinity  towards  the  tryptic 
ferment,  the  temperature  necessary  to  destroy  its  activity  rising  from 
65 0  to  700.    In  a  neutral  medium,  the  temperature  falls  to  550. 
Unfiltered  fresh  saliva  loses  its  diastatic  properties  at  750,  filtered 
saliva  at  700,  diluted  saliva  at  6o°,  pure  ptyalin  at  700,  unless  its 
solution  is  much  diluted,  when  the  necessary  temperature  sinks  to 
6o°.  The  influence  of  salts,  reaction,  etc.,  is  exactly  the  same  in 
kind  as  with  trypsin.  In  all  cases,  if  the  pure  ferment  be  used,  the 
influence  of  temperature  and  the  influence  of  salts,  etc.,  on  the 
temperature  are  more  easily  observed  than  if  the  ferment  be  impure, 
as  contained,  for  instance,  in  the  digestive  juice. 
The  explanation  of  these  occurrences  probably  lies  in  the  forma- 
tion of  loose  compounds  with  the  enzymes,  analogous  to  the  pepsin- 
hydrochloric  acid  of  Schmidt  and  other  authors. 
COFFEE-LEAF  TEA. 
Mr.  William  Sowerby,  the  veteran  and  distinguished  secretary  of 
the  Royal  Botanical  Gardens,  has  sent  to  the  British  Medical 
Jozcrnal  a  note  on  his  recent  pregnant  suggestion  for  adding  to  the 
number  of  alkaloidal  beverages  by  the  introduction  of  coffee-tea. 
When  walking  in  the  Gardens  of  the  Royal  Botanic  Society, 
Regent's  Park,  and  noting  the  extent  of  the  collection  of  living 
medicinal  and  economic  plants  of  all  climes  and  countries  there 
brought  together  in  one  spot,  it  must  have  occurred  to  all  of  us  how 
very  small  a  number  of  plants,  out  of  the  vast  store  which  Nature 
has  provided,  man  has  bound  tc  his  service,  and  the  yet  fewer  he 
