786 
/ 
Normal  Salt  Solution. 
Am.  Jour.  Pharm. 
Nov.,  19 18. 
Table  I. 
Original  Solution. 
Cc. 
Average  Con- 
tent of  NaCl 
in  Three 
Treated  at 
Different 
Occasions  as 
Determined 
by  Titration, 
Average  Loss 
of  Water 
Determined 
ing  and 
Calculation, 
Content 
Determined 
by  Titration 
with 
ag  N03V.  S., 
Per  Cent. 
Per  Cent. 
Per  Cent. 
Original 
1 
— 
O.85 
Sterilized  in  autoclave  at  15-lb. 
1,000  flask 
2 
.871 
2-4 
pressure  for  20  minutes. 
500  " 
3 
.860 
1. 17 
100  " 
4 
.882 
3-76 
Sterilized   by  boiling  for  one 
1,000  " 
5 
1-075 
26.4 
hour. 
500  " 
6 
.946 
II. 2 
100  " 
7 
1. 194 
4O.4 
Sterilized  by  heating  in  steam 
1,000  " 
8 
0.85 
No  loss 
for  one  hour. 
500  " 
9 
0.85 
100  " 
10 
0.85 
From  these  experiments,  if  we  strike  a  further  average  between  the  dif- 
ferent sets  used  from  flask  2,  3,  4,  we  will  obtain  an  average  loss  of  2.4  per 
cent,  moisture,  which  will  give  a  salt  content  of  .871  per  cent.  Sets  5,  6  and  7 
will  give  an  average  loss  of  26  per  cent,  moisture,  which  in  turn  will  give  a 
salt  content  of  1.07  per  cent.  Sets  8,  9  and  10  show  no  loss  at  all.  Whether 
this  method  is,  however,  effective  as  a  means  of  sterilization  will  be  reported 
in  another  paper  later  on. 
From  these  experiments  we  are  led  to  the  conclusion  that  heat- 
ing in  the  steam  sterilizer  is  the  best  sterilization  method  to  be  em- 
ployed by  the  average  physician  and  practitioner  so  as  to  avoid  con- 
centration of  the  solution.  The  autoclave  (if  at  hand)  is,  of  course, 
to  be  preferred  as  it  is  undoubtedly  a  more  effective  method  of  ren- 
dering rcaterial  sterile,  while  an  average  concentration  to  .871  per 
cent,  of  sodium  chloride  will  not  bear  any  marked  relationship  to 
the  isotonicity  (.85  per  cent.)  of  the  end  product.  But  mere  boil- 
ing is  not  to  be  recommended,  unless  the  wTater  of  evaporation  be 
directed  to  be  replaced  by  freshly  distilled  sterile  water.  In  addi- 
tion to  bearing  perhaps  only  a  slight  relationship  to  the  isotonicity  of 
the  physiologic  solution,  the  product  that  will  be  used  from  time  to 
time  will  vary  greatly  depending  upon  the  size  of  the  container  used, 
the  amount  of  solution  that  is  boiled  and  the  activity  of  the  boiling, 
and  if  for  no  other  reason  than  for  more  constant  uniformity  in 
preparations,  the  recommendations  offered  should  be  considered. 
It  might  be  interesting  to  consider  and  observe  what  effect  salt 
