Chap. XIIL] ROTIFERA AND PASTE-EELS. 487 
But although these different species may die and be re- 
suscitated several times in succession, this power has its 
limits, and each successive experiment generally proves fatal 
to one or more individuals. Spallanzani, in his experiments 
on the Rotifera, did not find that any survived after the six- 
teenth alternation of desiccation and damping, but paste-eels 
bore seventeen of these vicissitudes. 
Spallanzani, after thoroughly drying sand rich in Rotifera, 
kept it for more than three years, moistening portions taken 
from it every five or six months. Bakee went further still 
in his experiments on paste- eels, for he kept the paste from 
which they had been taken, without moistening it in any 
way, for twenty-seven years, and at the end of that time the 
eels revived on being immersed in a drop of water. If they 
had exhausted their lives all at once and without these inter- 
missions, these Rotifera and paste-eels would not have lived 
beyond sixteen or eighteen consecutive days. 
To remove all doubt as to the complete desiccation of the 
animalcules experimented on by Spallanzani and Bakee, M. 
Doyeee has published, in the Annates des Sciences Naturales 
for 1842, the results of his own observation, in cases in 
which the mosses containing the insects were dried under the 
receiver of an air-pump and left there for a week ; after which 
they were placed in a stove heated to 267° Fahr., and yet, 
when again immersed in water, a number of the Rotifera be- 
came as lively as ever. 
Further particulars of these experiments will be found in 
the Appendix to the Rambles of a Naturalist, &c, by M. 
QlJAETEEFAGE. 
II 4 
