28 GEOEGE JOHN EOMANES 1875- 



last from a minute to half an hour. This motion is 

 totally different from anything exhibited by the 

 animal when alive, and after ceasing never recom- 

 mences without fresh stimulation. The shivering 

 appearance, I think, is due to the various systems of 

 muscles contracting without co-ordination, but why 

 it should take place in some cases and not in others, 

 I am quite unable to determine. 



Irritability of bell to shocks increases progres- 

 sively from centre to circumference, and is greatest 

 when electrodes are placed on marginal canal. Also 

 a similar progressive increase is observable on ap- 

 proaching one of the radial canals, and is greatest 

 when electrodes are placed on one of these. (I may 

 observe that however neat a person's fingers may be 

 it would be simply impossible to conduct these 

 and other observations of the same nature without 

 a mechanical stage. The electrodes must be needle- 

 points passed through cords, the latter being sup- 

 ported by a copper wire fixed to the stage, and 

 therefore moveable with it ; and I defy anybody to 

 get the electrodes into the field, and at the same 

 time upon the marginal canal, unless they all move 

 together.) 



Sarsia stands an astonishing amount of section 

 without losing nervous conductibility. For instance, 

 the whole organism may be cut into a three-turned 

 spiral, and on irritating the end, the whole contracts ; 

 yet a moment's thought will show how trying this 

 mode of section is to nervous connections. As the 

 animal may be cut, as in the following diagram, 

 which represents the whole organism in projection — 



