150 
moment to append a frank confession that they necessitate 
the admission that the explanation of amoeboid move- 
ment brought forward by him ‘‘is inadequate.” Even 
on this point, therefore, his experiments have not fur- 
nished a tenable theory applicable to free protoplasmic 
forms. Add this to the author’s other admission that. in 
his oil foams ‘‘ nothing was ever observed of a rotational 
streaming such as occurs so commonly in vegetable cells,”’ 
and we are left in wonder as to what possible application 
his experiments can have to biological problems of any 
kind. 
We have given so much attention to Professor Biitschli’s 
main contention that our space does not permit of a review 
of his less important arguments. It must therefore suffice 
to say that his criticisms of the various theories of proto- 
plasmic structure are able and interesting. 
The objects of his animadversions aie, however, prin- 
cipally those who, like Velten, Briicke and Heitzmann, 
have held to the necessity of an organization in protoplasm 
made up of more solid and more fluid parts, the more 
solid constituting the active reticular structure in which 
resides the power of contractility, the more fluid being the 
passive contents of the living meshwork. All that needs 
to be said on this point is that the theory of Heitzmann is 
a fair attempt to account for actually observed phenomena 
in natural organisms, while the speculations of Biitschli do 
not appear to explain satisfactorily the behavior of even 
his own creations. 
LETTERS TO THE EDITOR. 
+*, Correspondents are requested to be as brief as possible. The writer’s name is 
in all cases required as a proof of good faith. 
On request in advance, one hundred copies of the number containing his communi- 
cation will be furnished free to any correspondent. 
The Editor will be glad to publish any queries consonant with the character of the 
journal. 
Earth Worms. 
THE earth worm notes and comments which have been 
published in recent numbers of Scvence have been of 
considerable interest to the writer, and this opportunity 
is taken to offer a few notes of observation, made at 
various times, bearing on the question of the cause of the 
appearance of large numbers of earthworms in rainy 
weather. 
While it is not uncommon to read or hear of what are 
apparently well authenticated instances of ‘‘ showers” of 
frogs, tadpoles, and fish, it is very rare to hear of any 
one who has seen earth-worm showers. Yet among the 
unobservant, the commonly received explanation of the 
occurrence of these animals in the large numbers that 
appear on our city and village sidewalks and pavements, 
during rain storms, is that they ‘‘rain down.” 
The habitat of the aquatic and amphibious animals 
makes it possible to accept as true the accounts of falls 
of such forms, because they might be taken up into the 
air with the water in which they live by some sudden strong 
uprush of air, as a tornado, but it is difficult to imagine 
conditions under which the burrowing earthworm could 
be raised to a position from which it could ‘‘rain down.” 
The worms which appear during rain can be satisfac- 
torily accounted for, if a reason sufficient to bring them 
out of the ground can be found. Each square foot of 
loamy soil has, among other inhabitants, one or more 
earthworms living in it, so that the grass borders of 
streets and walks, even in large cities, harbor myriads of 
these animals and the soft earth in less thickly settled 
communities hides numbers of them beneath its surface. 
Granted, then, the presence of the worms near at hand 
to sidewalks and pavements, cause adequate to bring them 
out of the earth during the rain and to make them wander 
about must be found. An explanation readily suggests 
SCIUNGE: 
Vol. XXIII. No. 580 
itself, from the fact that the burrows of the animals must 
be full of water when it is raining, and it would seem that 
they would have to come to the surface or drown, and for 
a long time the writer was satisfied that this theory ex- 
plained the appearance of the worms. 
The following facts, noted at different times, tend to 
show that the explanation is not sufficient: 
A number of years ago, while preparing some earth- 
worms ‘for use in a zodlogy class, I was washing them in 
atank of running water, the source of supply being a 
small faucet tapping the village mains, the ultimate source 
being a small river. In the tank, which was of galvanized 
iron, were several crayfish, a few specimens of Onodonta 
and other mussels, and some snails. During the washing 
process, several of the earthworms slipped away into the 
tank, and they were left there to serve for food for the 
crayfish. There was no sand or earth in the tank, except 
a small quantity of sediment which had accumulated from 
the water and its inhabitants, and this was not over an 
eighth of an inch deep in the deepest place. Within a 
short time, all of the animals, except one very large 
specimen of a species of unio, were taken from the tank, 
and wishing to keep the unio alive, the water was not shut 
off, but left running in a small stream through the winter 
and the following summer.. The next fall, having to use 
the tank for another purpose, the unio was removed and 
the tank cleaned. When the water was allowed to run 
out, in the bottom of the tank was found a large and 
active earthworm. ‘The room was a private one, of which 
I carried the only key, and there had been no earthworms 
in it since the previous year, and the opening through 
which the water entered the tank was only sufficient to 
admit a slender stream of water, just sufficient to keep up 
circulation in the tank. The worm was carefully examined 
to make sure of the identity of the species, and it was 
permitted to escape. The sediment in the bottom of the 
tank was largely vegetable in its origin, and was of such 
character as to furnish abundant food for an earthworm, 
but was even at the end of the year hardly as deep as the 
worm was thick. The tank was about a foot deep, and 
the worm had lived about a year in that depth of water. 
A second case came to my notice while collecting cray- 
fish in a small river in this vicinity. The water in the 
part of the stream where the collecting was done was a 
little less than knee deep and the stream about forty feet 
wide. he crayfish hide under water-logged slabs and 
pieces of bark from the mills above, and to catch them 
the wood has to be moved. Under a slab in the middle 
of the stream was found a live and active earthworm, 
which was not buried in the mud, but lying immediately 
on the surface of it under the slab. There had been no 
rain for several days, and it was not probable that the 
worm had been washed into the stream from the bank. 
These instances, together with the fact that these animals 
are frequently abundant in soil that is saturated with 
water, and the observations and records of similar and 
more numerous cases of the same sort, noted by Darwin 
in his work on the ‘‘ Formation of Vegetable Mould,” 
tend to make it plain that the earthworm is not driven 
out of its burrow because it fears water. 
Fyom these considerations it is probable that still other 
causes to explain the phenomenon must be sought, but it 
is not my purpose to offer any theory in explanation. 
The following facts, however, may suggest a line of 
approach, along which~ investigation may be made by 
those disposed to attempt to work out the problem. Ifa 
light tapping be made on the surface of ground inhabited 
by earthworms, they will come to the top of their burrows, 
and if the tapping is kept up they will finally crawl entirely 
out of the ground. ‘The birds are well aware of this fact, 
and robins, in particular, make use of their knowledge of 
