JANUARY 18, 1884.] 
the initial croak would come from one side of 
the pond, then the other, and so continue to 
vary. This shows at once that not any one 
individual started and stopped the croaking of 
its companions. 
Hoping to find that in the pursuit of prey, 
which is principally insects, frogs would dis- 
play some intelligence, I tried several experi- 
ments to test their ingenuity; but it was of 
no avail. Unless the food could be easily 
reached by making the simple exertion of a 
single leap, the frogs would go hungry. Sub- 
sequently I placed a large fly upon a piece of 
thin mica, and surrounded it with a circle 
of fine needles, piercing the plate. The fly 
thus protected could only be seized by the frog 
suffering a severe pricking of the jaws. ‘This, 
I found, a frog would suffer indefinitely, in its 
attempts to secure the fly. In one instance, 
the frog, which had been fasting for seventy- 
two hours, continued to snap at the needle- 
protected fly until it had entirely skinned its 
upper jaw. I concluded from this, that the 
wits of a frog were too limited to be demon- 
strated. 
Some weeks after having completed these 
experiments, I had the good fortune to cap- 
ture two fully grown specimens of the bull- 
frog (Rana Catesbyana) ; and, noticing their 
enormously distended sides, I examined the 
stomach-contents of the two. In one was a 
full-grown chipmunk (Tamias striata) ; in the 
other, a garter-snake (Eutania sirtalis) meas- 
uring eighteen inches in length, and also a 
field-mouse (Arvicola riparia). On close ex- 
amination, I found that the snake had partially 
swallowed the mouse ; and, while thus helpless, 
the frog had evidently attacked the snake, and 
swallowed it. 
It is evident, I think, that the frog recog- 
nized the helpless condition of the snake at 
the time, and took advantage of it. If so, it 
is evidence of a degree of intelligence, on the 
part of the frog, which the results of my ex- 
periments on the frogs generally, had not led 
me to expect. Certainly a frog, however large, 
will not attack even a small snake if it is pos- 
sessed of its usual activity. 
The salamanders, on the other hand, by 
their active movements, wandering disposition, 
quickness of hearing, and other minor charac- 
teristics, give evidence of greater intelligence. 
This I can state of them, however, as an im- 
pression only; for my efforts to prove them 
possessed of cunning were not successful. The 
purple salamander, it is true, fights when cap- 
tured, curving its back, and snapping vicious- 
ly. This no frog ever does. The common 
SCIENCE. 
67 
spotted triton (Diemyctelus) becomes quite 
tame when kept in an aquarium, and, as I 
found, is soon able to determine the difference 
between a fly held against the glass and one held 
over the water. I frequently held a fly against 
the glass, and very near the triton ; but it took 
no notice of it, after one or two efforts to seize 
it, but would follow my hand, and, when the 
fly was held over the surface of the water, the 
triton promptly leaped at and seized it. This 
is, indeed, but meagre proof of intelligence, 
but seems to show, I think, that a salamander 
is more cunning than a frog. 
My observations lead me to conclude, that 
the habits of an animal have much, if not all, 
to do with the intellectual capacity it possesses. 
Frogs, as a class, are not migratory. They fre- 
quent a given pond or stream; and, sustained 
by the insect-life that comes to them but is 
not sought, they pass an eventless life, trust- 
ing, as it were, to luck. Such an existence 
requires no intellectual exertion, and none is 
made. ‘The salamanders, on the contrary, are 
far more wandering and active. They appear 
to be ever in search of food, and, when lying 
in wait for it, choose such positions as experi- 
ence has taught them are best adapted for the 
purpose: at least, my studies of such speci- 
mens as I have kept in confinement lead me 
to believe so. Intellectually, therefore, the 
salamanders are in advance of the frogs; but 
the batrachians as a class, although higher in 
the scale of life than fishes, are, I believe, in- 
ferior to them in intelligence. 
Cuas. C. Appott, M.D. 
THE PONS-BROOKS COMET. 
Tue comet which is now being observed at 
its first predicted return was discovered by 
Pons, at Marseilles, two hours after midnight 
of July 20, 1812. Pons was at the time 
concierge at the Marseilles observatory, but 
afterwards became its director. He died in 
Florence, Oct. 14, 1831, at the age of seventy, 
having, between the years 1801 and 1827, dis- 
covered no less than thirty-seven comets ; this 
one, according to Zach (Monatl. corr., xxvi. 
270), the sixteenth in ten years. 
Pons describes the comet at the time of 
discovery as an irregular, nebulous mass, with- 
out coma or tail, and invisible to the naked 
eye. Having made sure, from the motion, 
that it was really a comet, he announced his 
discovery on July 22; and, from July 25 to 
Aug. 3, it was bright enough to be observed, 
at lower culmination, with the Marseilles in- 
