470 
Assay  of  Heart  Tonics. 
J  Am.  Jour.  Pharni. 
t     October.  1909. 
able  for  manufacturers  in  all  countries  to  adopt  the  same  standard, 
as  was  recently  pointed  out  and  urged  by  one  of  us  (Houghton. 
London  Lancet,  June  19,  1909). 
A  possible  explanation  for  the  loss  in  activity  of  preparations  of 
digitalis  may  be  that  it  is  due  to  a  ferment  which  is  not  destroyed 
by  the  menstruum,  as  pointed  out  by  Rosenthaler  and  Mever 
or 
TABLE  VI. 
FLUID  EXTRACT  DIGITALIS .  T'TH  REVISION. 
No. 
5 
3 
2 
4 
4 
8 
7 
8 
10 
4 
2 
5 
2 
M.  F.  D. 
Units. 
0008 
.0009 
.0010 
100 
.OOII 
91 
.0012 
83 
.0013 
77 
.OOI4 
7i 
.0015 
66 
.0016 
62 
.0017 
58 
.0018 
55 
.0019 
52 
.0020 
50 
.0021 
47 
.0022 
45 
.0024 
4i 
.0027 
37 
.0030 
33 
.0031 
32 
.0032 
3i 
•0035 
28 
.O066 
15 
.0075 
13 
Sum  Diary — Fluid  Extract  Digitalis,  ~th  Rev. 
M.  F.  D. 
Standard  adopted  in  1898  
Average  for  83  samples  tested  since 
Proposed  standard  for  7th  Rev.  U.  S. 
.001 
1 901 
P.  . 
H.  T.  U. 
per  Cc. 
66 
70 
65 
again  it  may  well  be  that  these  products  are  acted  upon  in  a  detri- 
mental way  by  the  soluble  constituents  in  the  glass  used  in  the  bottles 
for  storing  the  material  (see  "Dictionary  of  Chemical  Solubilities.'" 
Comey).  Certain  it  is,  American  glassware  varies  a  great  deal  in 
its  composition.  This  strikingly  came  to  our  notice  in  connection 
with  the  use  of  test-tubes  for  growing  cultures  of  bacteria.  In 
some  instances  the  glass  contained  sufficient  alkalinity  to  inhibit  the 
growth  of  the  germs  entirely.    Indeed  it  has  been  a  source  of  con- 
