SENSIBILITY WITHOUT NERVES. 405 



they are contractile ; and we are not warranted in 

 calling every contractile cell a muscle-cell ; otherwise we 

 must call the unicellular animals muscles.* The Hydra 

 presents us with contractile substance (or cells), but 

 to call the contractile substance a " muscle/' is to out- 

 rage language more than if a wheelbaiTow were spoken 

 of as a railway locomotive ; and even this latitude of 

 language will not serve our turn with respect to the 

 nervous system of the Polype, since nothing resembling 

 a nerve or nerve-substance is discernible in it. We 

 must either deny that the Polype manifests Sensibility, 

 or we must admit that Sensibility may exist without 

 nerves. 



In presence of these facts, physiologists, who cannot 

 conceive Sensibility without a nervous system, but are 

 forced to confess that such a system is undiscoverable, 

 assume that it exists " in a diffused state.'' I have 

 noticed this illogical position in a form er» chapter. It 

 is a flat contradiction in terms : a diffused nerve is 

 tantamount to a liquid crystal ; the nerve being as 

 specific in its structure, and in the properties belong- 

 ing to that structure, as a crystal is. Now, this speci- 

 fic structure — or anything approaching it — is not to be 

 found in the Polype.f 



* Victor Carus aud Reichert have discovered contractile cells in 

 the vitellus, but no one wo^^ld call these muscles. 



f ''Sarebbe una vera perdita di tempo," says Delle Chiaje, "per 

 colui che volesse ricercare nervi negli animali Infusori, nei Polipi, nolle 

 Meduse e nolle Actinie." — Istituzioni di A nat. e Fisiolog, ComjKirata, i. 

 118. He denies the existence of nerves even in the Holotburise. So 

 likewise does Vogt, Zoologische Brief e, with several other anatomists. 



