DISTRIBUTION OF B. COLI COMMUNE 
125 
removed and the plate incubated. At first the shape of the paper is shown after 
incubation as a solid mass of growth, after six hours drying (No. 4, Table J\ Exp. II) 
there were only a few scattered colonies, and after ten hours drying (No. 5, Exp. II) 
the patch remained quite sterile. This test, of course, is not so searching as incubating 
the paper with broth for twenty-four hours and then plating the broth culture. 
This makes it easy to understand how it is that one frequently does not rind 
any trace of the B. coli in places where it must undoubtedly have been present in 
quantity not so very long before, e.g., in roads, manured land, &c. The effect of 
drying, shown in the above experiments, would account for its absence. A question 
of practical interest arising out of this is whether the streets should be watered or 
not in the dry weather. Mazuschita (Arcbiv.f. Hygiene, 1899, 35, 252), found in 
Freibury- that the life of certain bacteria in watered dust was three times as long: as 
in dry dust, and also that on an average there were twice as many organisms in the 
dust of a watered street as in that ot one which was unwatered. He considers that 
although the watering of streets lengthens the life of the bacteria in the dust, that it 
is still useful in laying it, and thus keeping it away from the respiratory organs ; as 
an improvement he would suggest thoroughly flushing the streets at frequent 
intervals. 
In conclusion, I wish again to give my best thanks to Professor Boyce, at 
whose suggestion the work was originally undertaken, and to whom I am indebted 
for much kind help and advice during the course of the investigation. 
TABLE III 
No. 
Date 
Description and Source of Sample 
Dilution used 
Presence or Absence 
B. coli in quantity 
analysed 
Remarks 
I 
1900 
May 1 
1 
Absent in .2 grm 
Dry weather 
2 
» I 
Dust of roads 
• 16 „ 
Dry weather 
3 
1 
Dry weather 
4 
„ I 
J 
• 15 „ 
Dry weather 
s 
» 7 
Dirt, side of road, Bedford St., L'pool. 
"65,000 per grm. 
Damp weather 
6 
„ „ Walnut Street, ,, 
1,200 „ ,, 
Damp weather 
7 
„ 7 
Puddle water, Ashton Street, „ 
W 
500 ,, c.c. 
Damp weather 
8 
„ 7 
„ ,, Huskisson Street, „ 
~50~ 
* 4,200 „ C.C. . 
Damp weather 
9 
„ 7 
„ ,, Bedford Street, „ 
! 
~W 
750 „ C.C. 
Damp weather 
10 
» 7 
Neat 
25 » c.c. 
Damp weather 
1 1 
» !5 
Dirt, middle of road, Edge Lane, „ 
.2 grm. in 50 c.c. 
Abs. in .012 grm. 
Dry sample 
;* 
. .5 
„ side of road, ,, ,, ,, 
1. 1 8 ,, ,, 50 c.c. 
Abs. in .07 ,, 
Dry sample 
" 15 
„ ,, Marmaduke Street, ,, 
.98 „ „ 50C.C. 
Abs. in .06 ,, 
Dry sample 
B 
