•602 
Number  of  Bacteria  in  Ice. 
/  Am.  Jour.  Pharm. 
1       Dec.,  188ft. 
piece  of  ice,  about  double  the  size  of  one's  fist,  was  detached  from  the 
surrounding  mass,  washed  with  distilled  sterilized  water,  and  put  into 
a  sterilized  glass  vessel.  As  soon  as  several  grams  of  ice-water  had 
collected,  a  measured  quantity  was  mixed  with  meat-solution -pepton- 
gelatin,  and  poured  on  glass  plates.  The  author  again  insists  on  the 
necessity  of  examining  the  water  directly  after  the  ice  melts. 
A  small  quantity  of  ice  having  thawed,  as  equable  a  mixture  of 
the  constituents  as  possible  was  made  by  shaking,  and  1  ccm.  of  this 
water  introduced  into  nutrient  gelatin  by  means  of  sterilized  pipettes. 
As  a  rule  one  ccm.  water  was  introduced  into  two  tubes,  and  J 
ccm.  into  other  two.  These  last  served  in  some  measure  to  control 
the  results,  and  ought  to  contain  half  as  many  germs  as  the  first  two. 
The  contents  of  the  test  tubes  were  then  poured  on  glass  plates  in  the 
usual  manner.  The  time  required  for  the  germs  contained  in  ice  to 
attain  complete  development  varied  with  the  temperature  of  the 
place  where  the  plates  were  kept.  It  usually  ranged  between  three 
and  four  days.  The  colonies  were  counted  in  the  usual  way.  As 
with  water,  a  large  number  of  examinations  were  made  of  the  same 
ice.  The  first  ice  examined  was  that  of  the  North  German  Ice-works 
in  Berlin,  the  material  being  described  as  "Natural"  or  "Raw"  ice. 
This  ice  was  taken  in  winter  from  the  Rummelsburger  See,  a  lake- 
like extension  of  the  Spree  above  Berlin.  It  was  usually  collected 
when  the  ice  reached  a  thickness  of  15  to  20  cm.  and  was  laid  in 
large  keeping  compartments.  The  results  of  the  bacteriological  ex- 
amination of  specimens  of  this  ice  is  exhibited  in  a  long  table,  of 
which  the  commencement  is  here  given. 
Day  of  Counting. 
Interval  in 
hours. 
Day  on  which  Plate  Culti- 
vations were  made. 
1 5th  February,  1886 
16th         "  1886 
28  th         "  1886 
22nd         "  1886 
28th         "  1886 
1st  March,  1886 
2nd     "  1886 
19th  February,  1886 
20th        "  1886 
22nd       ".  1886 
26th        "  1886 
3rd  March,  1886 
5  th      "  1886 
6th       "  1886 
90  I 
90  I 
90  I 
92  { 
*  I 
94  { 
95  { 
Number  of  Colonies. 
Counted  in 
1  ccm. 
Counted  hi 
J£  ccm. 
220 
116 
218 
102 
318 
228 
472 
224 
314 
140 
260 
120 
6,300 
2,700 
5,580 
3,300 
158 
70 
164 
90 
920 
440 
800 
4f'0 
80 
50 
86 
44 
