Crosse’s Experiments with the Voltaic Battery. 129 
these little mites, when so excellent a one has been transmitted 
from Paris. It seems that they are of the genus Acarus, but of 
a species not hitherto observed. . I have had three separate forma- 
tions of similar insects at different times, from fresh portions of 
nee e fluid, with the same apparatus. As I considered the 
of this experiment rather extraordinary, I made some of 
os friends acquainted with it, amongst whom were some highly 
scientific gentlemen, and ee plainly perceived the insect in va- 
rious states. I likewise transmitted some of them to one of our 
most distinguished physiologists in London, and the opinion of 
this gentleman, as well as of other eminent persons to whom he 
showed them, coincided with that of the gentlemen of the Acade- 
mie des Sciences, as to their genus and species. J have never 
ventured an opinion as to the cause of their lirth, and for a very 
good reason—I was unable to form one. The most simple solu- 
tion of the problem which occurred to me, was, that they arose 
from ovadepesited. by insects floating in the atmosphere, and that 
they might possibly be hatched by the electric action. Still, I 
could not imagine that an ovum could shoot out filaments, 
that those filaments would become bristles ; and moreover, I 
could not detect, on the closest examination, any remains of a 
shell. Again, we have no right to assume that electric action is 
necessary to vitality, until such fact shall have been most dis- 
tinctly proved. I next imagined, as others have done, that they 
might have originated from the water, and consequently made a 
close examination of several hundred vessels, filled with the same ~ 
water as. that which held in solution the silicate of potassa, in 
_the same room, which vessels constituted the celle of a large Viale 
taic battery, used without acid. In none of vessels. 
I perceive the trace of an insect of that des . likewise 
closely 
examined the crevices and most. aepegidiiet the room 
with no better success. In the course of some months, indeed, 
these insects so increased, that when they were strong enough to 
leave their moistened birth-place, they issued out in different di- 
rections, I suppose, in quest of food ; but they generally huddled 
together under a card or piece of paper in a, as 
