110 Dr Rusconi’s Observations on the Natural History 
and sixth days, when, instead of the young animals which he ex- 
pected to come forth, the eggs had lost their transparency, had 
become covered with mould, and their faculty of evolution was 
destroyed. 
During this time, the salamanders, which were left in the 
tub, had deposited other eggs, which he collected as before ; 
and, suspecting that the water he had used might have been 
improper for the purpose, he now employed that taken from the 
ditches in which the animals had lived ; but with no better suc- 
cess. He next had recourse to methods of artificial impregna- 
tion, previously executed with success by Spallanzani ; but failed 
in these also. While engaged, however, in these experiments, 
he observed.that the salamanders, which had been left in the tub, 
pressed back, from time to time, their hind-limbs beneath the 
belly, and that, in a few moments afterwards, they laid one or 
two eggs ; these eggs did not fall always to the bottom of the 
water, but sometimes remained attached, for a moment, to the 
anus itself, in such a way that some of the salamanders might 
be seen, running here and there in the tub, with two or three 
eggs thus attached. It was not easy to form plausible conjec- 
tures upon this habit of pressing back the legs under the belly, 
when the eggs were laid. The mode even of their escape from 
the animal surprised the author, because, trusting to what 
M. Cuvier had written, he thought that these animals produced 
many eggs at once, which escaped in succession, and were at- 
tached to one another in the form of a necklace. Proposing, 
therefore, to investigate this point more minutely at another time, 
but occupied, at present, with the desire only of procuring for 
his salamanders a suitable habitation, he wished to make such 
arrangements as should enable the animals, during the night, to 
support themselves at the surface of the water, in order to respire 
with greater facility. At this time, a fresh parcel of these ani- 
mals happened to be brought to him in a pail, in which many of 
the plants called Polygonum Persicaria were placed, with the 
view of preventing the water from escaping out of the pail. Of 
some of these plants he made a packet, and placed them in his 
tub, under a large stone to confine them to the bottom. Towards 
evening, he visited the tub, and found all his salamanders so 
commodiously situate, by the aid of the plants, that, by keeping 
