242 Zoological Society :— 
The cellars in Nottingham, cut out of solid rock, are most favour- 
able for experiment; no solar light ever enters, and they are not 
subject to any great change of temperature. The deepest cellar is 
30 feet deep, the mean temperature 51° Fahr.; the middle cellar is 
18 feet deep, its mean temperature 53° Fahr. ; the uppermost cellar 
9 feet deep, mean temperature 56° Fahr. 
June 11th. In each cellar I placed a shallow glazed earthenware 
vessel, containing two pints of water, with grass for chlorophyll for 
food, changing the water every second day. In each vessel I put 
twenty tadpoles, approaching the period of their metamorphosis, fol- 
lowing the example of Dr. Edwards,—a much easier method than 
commencing with the spawn. 
In the uppermost cellar ten were fully developed in the form of a frog 
on the 8th of September, and were on the stones, having left the water. 
In the middle cellar ten were fully developed on the 22nd of 
September. 
In the lowest cellar eight only had left the water, being fully 
developed on the 20th of October. 
In the following year, July 1st, I made a similar experiment in 
the same cellars, three weeks later. The tadpoles were of a large 
size. I obtained the same result—the full development of the 
frog in the absence of light; but in this experiment I had another 
object in view, that of observing the growth and obtaining the exact 
weight of the tadpoles before, during, and after their metamorphosis 
into a frog. 
Dr. Edwards said that in his experiment ‘‘the tadpoles attained 
an extraordinary size, doubling or trebling their usual full weight ;” 
but he unfortunately does not mention any particular weight, or 
how long the tadpoles were preserved alive; in fact there is nothing 
definite. 
During my several years of experiments I did not observe any re- 
markable increase of weight or size as mentioned by Dr. Edwards, 
although my first experiment was from the ovum to the full develop- 
ment of the frog, and the two last when the tadpoles were approach- 
ing the period of their development. 
In my first experiment on the ovum, I never obtained a tadpole 
more than 8 grains in weight in the absence of light; but I found 
in a pool in the neighbourhood a number of tadpoles, some between 
11 and 15 grains in weight ; seven of them weighed 15 grains each. 
Of these large tadpoles I took twenty for my experiment, weighing 
altogether 264 grains, and averaging about 13 grains each. After 
their transformation the frogs weighed 93 grains, averaging about 43 
grains each,—those of 15 grains in the tadpole state only weighing 
5 grains as frogs, having lost two-thirds of their weight during their 
metamorphosis. 
Subsequent experiments have been in accordance with the above. 
