128 
LIFE, IN ITS LOWER FORMS. 
kingdom stand to higher animals, and minister less to the 
perpetuation of their own species than to the sustenance 
of man.” * 
The researches of MM. Ercolatii and Vella, + on the em- 
bryogeny and development of the Nematoid (thread-like) 
Intestinal W orms, have revealed some details which, though 
not so startling as those discovered by Dr Von Siebold on 
the Tienioids, possess considerable interest. 
“ The Thread Worms do not undergo a true metamor- 
phosis ; the changes observable in the embryo are only 
phases of developments ; but as in the Tsenioids the gene- 
rative organs are the last formed, and are not perfect till 
the complete development of the animal. 
« The cessation of movement and the fluidity of the 
bodv in the Nematoids are not sufficient signs of the death 
of these animals, as they recover from this state as soon 
as they are placod in warm water ; even in the state of 
embryos, although completely dried up, they return to life 
very quickly by this means. The Nematoid worms con- 
sequently die with great difficulty ; the ova and embryos 
are endowed with a marvellous tenacity of life ; they even 
exhibit signs of life after immersion for six days in alcohol 
of 30 degrees. 
“ This tenacity of life, joined with the power of develop- 
ment of the ovum when placed in circumstances different 
from those in which it lives naturally, besides giving evi- 
dence of new and important facts, destroys the strongest 
arguments employed by many naturalists in favour of 
heterogeny. J 
. * Comp. Auafc. ; i. 76. (Edit, i.) 
i Comptcs Ttendus, 24th April 1854. 
X Heterogeny > a total difference of form between parent and offspring. 
