ON  FERMENTATION. 
445 
To  the  must  from  English  hot-house  grapes  a  known  quantity 
of  glucose  was  added,  and  the  liquid,  together  with  the  greater 
part  of  the  husks,  was  left  to  ferment  at  GS*^  F.  The  fermenta- 
tion ceased  in  about  twenty-three  days.  Another  sample  was 
permitted  to  ferment  at  75°  F.;  and  here  all  action  ceased  on 
the  sixteenth  day.  To  a  third  sample  such  amount  of  glucose 
was  added  as  to  bring  the  glucose  naturally  existing  in  the  juice 
up  to  40  per  cent.  In  this  case,  the  beginning  of  th(?  fermenta- 
tion was  delayed  much  beyond  the  usual  time ;  and  the  quantity 
of  alcohol  obtained  was  less  than  in  a  case  where  less  glucose  had 
been  added. 
In  all  cases  the  wine-ferment  proved  to  be  of  greater  fermen- 
tative power  than  the  malt  ferment. 
From  all  these  experiments  Mr.  Bell  deduces  the  conclusion 
that  it  would  be  advantageous  to  add  to  grape-juice  some  glucose, 
80  as  to  assist  the  exhaustion  of  the  must  of  its  fermentative  ele- 
ment, and  to  impart  thus  to  the  wine  a  greater  keeping-pov/er. 
In  some  instances  the  fermentation  was  started  in  the  grape-juice 
by  brewers'  yeast :  the  amount  of  alcohol  here  obtained  was  less 
than  in  the  cases  where  the  action  was  caused  by  the  natural" 
ferment  of  the  grape-juice. 
Finally,  Mr.  Bell  instituted  some  experiments  to  ascertain  the 
influence  of  change  of  soil;  and  the  results  in  connection  with 
the  observations  made  in  some  of  the  above  experiments  lead  to 
the  inference  that  the  various  ferments  have  their  favorite  soils. 
The  President,  in  asking  the  Fellows  to  vote  their  thanks  to 
the  author,  gave  a  hvief  resume  of  the  state  of  knowledge  we  at 
the  present  day  possess  of  the  yeast-plant.  Though  called  a 
■'^  plant,"  the  yeast  organism  appears  in  ail  its  functions  rather 
animal  than  vegetable.  The  products  of  its  secretion  are  less 
complicated  than  those  it  takes  in.  It  does  not,  like  plants,  re- 
quire light  for  its  vital  process;  neither  does  it  absorb  heat,  but 
on  the  contrary,  gives  such  off.  Prof.  Williamson  then,  alluding 
to  Leibig's  recent  memoir,  observed  that  this  distinguished 
chemist  has  entirely  dropped  his  ancient  notions  regarding  fer- 
mentation, though  he  somewhat  successfully  criticised  some  of 
Pasteur's  statements. — Proceedings  of  Chem,  Soc.^  in  Chemical 
News,  London^  June  24,  1870, 
