ACEPHALA LAMELLIBRANCHIATA. 33 



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 being 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 independent of 

 sensation, as Lamarck terms it, but by the agents and after 

 the manner I have just stated. 



" It 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 instru- 

 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 

 these 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 lines 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 inferior created animal being is not 

 without that portion of sensation or interior sentiment, and 



