Practical  Notes. 
{  Am.  Jour.  Pharm. 
(       Oct.,  1882. 
of  water  of  crystallization.  The  salt  is  made  by  ^directly  combining 
the  alkaloid  Avith  sulphophenic  acid,  or  by  de(;omposing  a  solution  of 
sulphophenate  of  lead  (or  of  barium)  by  means  of  quinine  sulphate. 
Since  the  salt  is  difficult  to  crystallize  it  is  best  dispensed  in  solution 
whicli  should  be  accurately  titrated. — Annali  dl  Chimica,  Ixxiv,  282. 
Ptrparation  of  Essence  of  Rennet  from  Fresh  Stomachs.  By  Dr. 
J.  Nessler. — In  this  paper  the  author  communicates  the  results  of  some 
experiments  made  with  the  object  of  comparing  the  activity  of  essence 
of  i-ennet  made  according  to  Soxhlet^s  method  from  dried  stomachs 
{"  Pharmaceutical  Journal  "  [3],  ix,  307)  and  that  of  essence  made 
from  fresh  stomachs. 
Tlie  experiment  showed  that,  using  corresponding  quantities  of 
dried  and  fresh  stomach,  the  latter  yielded  the  more  active  preparation. 
It  was  found,  moreover,  that  the  activity  of  the  preparation  from  a 
fresh  stomach  could  be  increased  by  the  removal  of  mucus,  which  not 
only  made  it  more  bulky,  but  prevented  it  from  diffusing  the  milk  so 
readily,  and  that  this  removal  could  be  effected  without  injury  by 
means  of  blotting  paper.  Preparations  made  from  the  top  layer  of  the 
inside  of  the  stomach,  scraped  oif  with  a  knife,  proved  much  more 
active  than  others  for  which  the  residuum  was  used,  but  the  residuum 
contained  too  much  ferment  to  permit  it  to  be  left  unused. 
The  author  gives  the  following  instructions  for  the  preparation  of 
an  essence  of  rennet  from  fresh  stomachs.  Chop  up  a  fresh  calf's 
stomach  as  finely  as  possible,  pour  upon  it  two  liters  of  water  in  which 
100  grams  of  common  salt  has  been  dissolved,  and  shake  well.-  After 
twelve  hours  add  200  cc.  of  90°  alcohol,  and  allow  the  whole  to  stand, 
with  frequent  stirring,  in  a  closed  flask  for  three  weeks,  then  decant, 
and  add  sufficient  blotting  paper  to  cover  it.  After  several  weeks, 
during  which  the  vessel  must  be  kept  well  closed,  the  essence  of  rennet 
is  drawn  off  into  bottles  and  preserved.  A  liquor  prepared  in  this 
way  was,  when  fresh,  capable  of  curdling  6,000  times  its  volume  of 
milk,  and,  being  kept  in  a  well-corked  bottle,  it  was  found,  after  two 
years,  to  have  diminished  in  activity  only  from  1  in  6,000  to  1  in 
5,451. 
The  author  adds  that  distilled  or  rain  water  gives  a  more  active 
essence  than  spring  water,  and  that  it  is  advantageous  to  mince  the 
stomach  as  finely  as  possible. — Phai-m.  Journ.  and  Trans. j  Aug.  19, 
1882;  from  Pharmaceatische  Zeitung. 
Estimation  of  Glycerin. — Glycerin  mixed  with  volatile  solvents  is 
