372 
Laboratory  Notes. 
Am.  Jour.  Phariu. 
July,  1895. 
The  variations  in  the  properties  attributed  by  the  different  authori- 
ties can  only  be  accounted  for  upon  the  ground  that  the  samples  of 
aloin  experimented  upon  varied  greatly  in  purity. 
Upon  referring  to  the  samples  examined  by  the  writer  it  will  be 
noticed  that  a  distinct  ratio  exists  between  the  solubility  in  water 
and  the  solubility  in  ether ;  thus  number  one  is  soluble  in  800  parts 
of  ether  and  only  100  parts  of  water,  while  number  two  is  soluble 
in  2,500  parts  of  ether  and  70  parts  of  water.  The  presence  of  a 
small  amount  of  ether-soluble  resin  would  partially  account  for 
this  difference,  and  it  is  extremely  probable  that  strictly  pure  aloin 
is  soluble  to  a  less  extent  than  any  of  the  figures  given  ;  indeed 
one  sample  of  aloin  which  was  made  by  the  writer  was  soluble  in 
16,000  parts  of  ether,  but  as  further  experiments  are  being  made  in 
this  direction,  it  is  hoped  that  something  more  definite  regarding 
the  solubility  of  strictly  pure  aloin  can  be  reported  in  the  near  future. 
305  Cherry  Street,  Philadelphia. 
LABORATORY  NOTES  ON  PEROXIDE  OF  HYDROGEN, 
OIL  OF  WINTERGREEN  AND  OIL  OF  TURPENTINE. 
By  Charles  H.  La  Wall,  Ph.G. 
(Read  before  the  Pennsylvania  Pharmaceutical  Association,  June,  1895. ) 
Peroxide  of  hydrogen  is  a  recent  addition  to  the  U.  S.  P.,  and  it 
is  required  that  it  shall  contain  about  3  per  cent.,  by  weight,  of 
absolute  peroxide  of  hydrogen,  corresponding  to  about  ten  volumes 
of  available  oxygen. 
Manufacturers  of  this  preparation,  while  recognizing  the  fact 
that  the  solution,  as  commonly  made,  is  not  very  stable,  and  easily 
loses  strength  during  transportation  and  handling,  are  very  careful 
that  it  shall  not  contain  a  large  excess  of  the  dioxide  over  the  ten 
volumes  required. 
The  following  table  shows  the  volume  strength  of  twenty- 
five  samples  examined  during  the  past  few  months : 
Volume. 
Volume. 
Volume. 
Volume. 
1 
•  •  •  9-98 
8 
...  9-98 
15     .  .  9-84 
22  -  .  .  9-90 
2 
.    .    .  I0'02 
9 
.  .  .  10-23 
16  .  .  .  9-28 
23  .  .  .  10-02 
3 
•  •  ■'  9'33 
10 
.    .    .  I0-02 
17  •  •  •  9'35 
24  .  .  10-28 
4 
.  .  .  9-03 
11 
■    •    •  9-98 
18  .  .  .  10-28 
25  •  •  •  10-37 
5 
•  •  •  9"97 
12 
.  .  .  io'o6 
19  .  .  .  10-19 
6 
.  .  .  10*07 
13 
.  .  .  1016 
20  .  .  .  10*07 
Average  of  25, 
7 
.  .  .  10-25 
14 
.  .  .  977 
21  .  .  .  10-15 
9*94 
