ACEPHALA LAMELLIBRANCHIATA. 30 
to explain my reasons for not concurring in the views of that 
great naturalist. Lamarck contends that sensation, or interior 
sentiment, does not exist in the lower animals, and that in 
them all movements arise from irritabilities excited by exter- 
nal impressions: I demur to this doctrine, and firmly believe 
that no created bemg can exist and exhibit evidences of 
vitality, by motion, without having implanted in it a certain 
degree of sensation or interior sentiment, by the influence of 
which the nervous and muscular powers are put in action. I 
grant that external causes may produce motions and contrac- 
tions, not I think by exciting an irritability dependent of 
sensation, as Lamarck terms it, but by the agents and after 
the manner I have just stated. 
“Tt will be admitted that the sensations in the lower animals, 
which are the origin of the nervous and muscular influences, 
are of the most subdued qualities; and though the points of 
departure of the nerves, and the muscular supports dependent 
on them, may not be discernible by the most powerful imstru- 
ments, still I believe that they exist, and produce those move- 
ments which are observed in the monad as well as in man. In 
the superior and larger animals, we can perceive the causes of 
tiiese influences and admit their existence, because they are 
apparent ; and why not in the smallest, though they escape 
our vision? In the nearest fixed stars we can observe their 
proper motions, but in those which are plunged in the deeper 
regions of the sphere, these motions, though we may presume 
that they undoubtedly exist, are inappreciable. Why may we 
not apply a similar reasoning to the doctrine of the sensations 
or interior sentiment, and the resulting nervous and muscular 
influences, being implanted in the lowest as well as the highly 
organized animals, according to their several structures, and 
not consign vast classes to exist without sensation? It ap- 
pears to me that the lnes of separation between apathy, sensa- 
tion, interior sentiment, and intelligence, as laid down by 
Lamarck, are erroneous and arbitrary. I believe that apathy 
in its strict sense, as applied to animals, does not exist; and I 
repeat, that the most imferior created animal being is not 
without that portion of sensation or interior sentiment, and 
D 
