OF SENSATION AND THE SENSES. 475 



ventral cord, and the same result always ensued. The legs which lay 

 behind the scission no longer executed their function, but appeared as 

 dead. The segments of the body also became flaccid and motionless, 

 and only at isolated spots catchings of the muscles were to be observed. 

 If the caterpillar were now carefully opened it was seen that the 

 posterior portion of the stomach, namely, that which lay beyond the 

 scission, no longer exercised its peristaltic motion, and that its contents 

 no longer passed into the ilium, and also that the indigestible remains 

 contained in this portion, as well as in the colon, were no longer ejected, 

 but that entire part of the intestine appeared lifeless. The anterior 

 portion acted however as usual ; the caterpillar still ate and crept about 

 with its anterior legs as if fully enjoying its preceding state, dragging 

 its insensible lamed posterior portion along with it. If, lastly, the 

 scission which separated the nervous cord were very near the head, so 

 that thereby the lamed portion considerably preponderated over that 

 still capable of motion, the latter was likewise hindered in the full 

 exercise of its function, the caterpillar could then no longer crawl, 

 although it exercised the requisite motions with its anterior legs, yet 

 the preponderating lame posterior portion prevented its moving from 

 the spot. Upon the nervous cord being separated at so high a spot the 

 vital system was considerably affected, and the caterpillar soon ceased 

 to live, but the further backwards the cut was made the longer the 

 caterpillar lived, and the less was the exercise of its functions 

 disturbed. 



The irritability of the muscles beyond the point of separation was 

 not yet wholly lost by the cutting, they speedily contracted after con- 

 siderable pressure, but immediately became flaccid upon the removal 

 of the exciting cause. The motion of the stomach also continued at its 

 superior extremity, even when the nervous cord was cut through 

 between the second and third pairs of legs, as this portion of the 

 stomach received its own nerves from the pharynx ; but if this nerve 

 running from the pharynx was separated the peristaltic motion of the 

 anterior portion of the stomach likewise ceased, and the entire function 

 of digestion suddenly stopped. 



Hence the brain appears the true seat of the animating forces, which 

 are transmitted from it by means of the nerves to the most remote 

 organs. The more distant therefore from the brain the wound takes 

 place, the less is the disturbance that it occasions to the system., but 

 the closer to the brain the more fatal is the operation. 



