RATS 
PER 
YARD 
RATS 
PER 
YARD 
TYPICAL BALTIMORE "ROW- HOUSE" BLOCK -NUMBER 14-1:34,35 
SURVEYED JULY 9, 1947 
93 
SOLID BOARD FENCES 
WIRE FENCES 
BUILDINGS 
ALLEY 
• = ENTRY TO RAT BURROW 
± = RAT PASSAGE THRU FENCE 
OR WALL OF HOUSE 
= RAT TRAIL 
+,+ +, ETC. = VARYING CONCENTRATIONS 
OF GARBAGE 
0 
0 
12 
0 
0 
2 
12 
10 
2 
0 
6 
0 
0 
6 
5 
0 
0 
? 
55 
Figure 2. — The utilization ot a typical Baltimore row-house block by rats. 
4 
