SENSIBILITY WITHOUT NERVES. 389 



Nor is this all. What we metaphorically call " nervous 

 concluction " takes place not only in the absence of fibres, 

 but also in the absence of any nerves whatever. There is 

 nothing like the sharp angle of a paradox to prick the reader's 

 attention ; and here is one in all seriousness presented to 

 him. The fact is demonstrable, that both Contractility and 

 Sensibility are manifested by animals totally destitute of 

 either muscles or nerves. Some physiologists, indeed, misled 

 by the a priori tendency to "construct" the organism in lieu 

 of observing it, speak of the muscles and nerves of the sim- 

 plest animals ; because, when they see the phenomena of 

 Contractility and SensibiKty, they are unable to dispossess 

 themselves of the idea that these must be due to muscles and 

 neiTes. Thus, when the fresh-water Polype is seen captm-ing, 

 struggHng with, and finally swallowing a worm, yet refusing 

 to swallow a bit of tlu-ead, we cannot deny that it manifests 

 both Sensibility and Contractility, miless we deny these pro- 

 perties to all other animals. Nevertheless, the highest powers 

 of the best microscope fail to detect the slightest trace of 

 either muscle or nei-ve in the Polype. Leydig, indeed, de- 

 scribes and figures what he calls the muscles of the Hydru.* 

 But what are they ? A network of contractile cells of irre- 

 gular shape, such as Ecker -f- had previously described as the 

 " unformed contractile substance," with this difierence, that 

 Leydig discovers a nucleus attached to the wall of eacli cell. 

 I have not been able to verify this observation myself mth 



* Op. cit. 



t Ecker] zur Lehre vom Ban und Lehen der coniractilen Substanz der 

 niedersten Thiere. 



