278  Estimation  of  Cocaine  by  Mayer's  Reagent.  {^j^wS™* 
1  c.c.  of  Mayer's 
Strength  of                                                         Reagent,  l/2  strength, 
Cocaine  Solution.                                                 precipitates  of  Cocaine : 
1:200  0-0062 
1  :  300  0-0066 
1 :  400  0-0070 
1:500  .  0-0074 
1 :  600  0  0078 
Or,  we  may  make  the  correction  for  excess  of  reagent  as  already 
explained.  The  following  table  may  also  be  of  service  in  interpreting 
results  : 
Quantity  of  Mayer's  reagent,  h  strength,  required  to  precipitate  a  given 
quantity  of  cocaine. 
Quantity 
of 
Cocaine. 
Measure  of 
Fluid  titrated 
5  c.c. 
Measure  of 
Fluid  titrated 
10  c.c. 
Measure  of 
Fluid  titrated 
15  c.c. 
Measure  of 
Fluid  titrated 
20  c.c. 
•010 
1-6 
•020 
27 
3-1 
•030 
4-2 
4-6 
•040 
5-3 
5'7 
6-2 
•050 
6-4 
68 
7-3 
•060 
7-9 
8-4 
•070 
9-0 
9-5 
•080 
10-6 
•090 
117 
•100 
12-8 
Results  of  any  titration  higher  or  lower  than  those  included  in  the 
table  are  beyond  the  limits  of  dilution  or  concentration  admissible, 
and  would  call  for  repetition  of  the  experiment.  In  conclusion  I  will 
only  add  that  cocaine  is  by  no  means  exceptional  in  its  deportment 
towards  Mayer's  reagent,  and  the  calculation  of  results  requires  in  all 
cases  an  application  of  similar  principles. 
April  28,  1886. 
Pereirine  in  Intermittent  Fever.— Dr.  Clemente  Ferreira,  of  Brazil, 
{Bullet,  gen.  de  Therap.,  April  15,  1886),  reports  a  number  of  cases  of  intermit- 
tent fever  treated  successfully  with  hydrochlorate  of  pereirine  after  quinine 
and  arsenic  had  been  tried  in  vain.  He  administers  thirty  grains,  divided  into 
four  doses,  beginning  four  hours  before  the  expected  chill,  half  an  hour  being 
allowed  to  intervene  between  the  doses.  This  effectually  prevents  the  paroxysm, 
which,  however,  may  return  on  the  following  day.  On  the  third  day,  the  med- 
ication is  repeated  as  before,  and  after  that  the  fever  does  not  reappear.  The 
value  of  pereirine,  according  to  the  writer,  is  equally  great  in  the  treatment  of 
irregular  paludic  manifestations. — N.  Y.  Med.  Jour.,  May  8,  1S86. 
