1889.] The Effect of Rain on Earth-Worms. 689 
dry earth as large as his two hands, there were seven burrows 
as large as goose quills (p. 160). If the numbers observed here 
above the surface are any good index to those below, their total 
number must be simply enormous. 
The mortality among the worms, as shown by the number of 
dead ones, is immense. Taking the number as given above for a 
single acre — 53,767 — we find there are five to every four square 
feet, or 1 1^ for every square foot of surface. Calculating the 
area observed in Franklin Square and the number there seen, we 
find one worm for every one and a half square feet. In the 
same way the number seen on Fifteenth street was one to every 
five and a half square feet, and in the Smithsonian grounds one 
in every nine square feet of surface. It should be remembered 
that the larger part of these were dead, and if, as in the case of 
Franklin park, one for ever>' one and a half square feet out of a 
possible five in every four square feet die, it is easily seen that 
the mortality is enormous. If this proportion holds out in any 
way at all over the two hundred and seventy and odd miles of 
streets in Washington, what an epidemic among the worms there 
must have been during the three-days rain referred to. 
Again, what is the cause of the mortality ? We cannot say 
they are crushed by the feet of pedestrians, because man>' of them 
show no signs of injury. It would seem as if, attracted to the 
surface by the moisture, they crawl out upon the hard asphalt or 
gravel, and then finding it impossible to return to Mother Earth, 
die on account of exposure, or are drowned in the deluge of 
water, many meeting death in the last form. 
