56 On the Reflex Function of the Spinal Marrow. 



Touch, in narcotized frogs and other animals, are only pro- 

 duced through the medium of the spinal marrow and brain, 

 may be decisively proved ; for if a limb be cut off' from a 

 narcotized frog, touching it (the limb) will not produce 

 twitchings in it. These experiments are still more instruc- 

 tive in the lizard. 



"The spotted lizard retains for a long time after division of 

 the spinal marrow, the so-named sensitive power in all parts 

 below the section ; or, if this cannot be called sensitive power, 

 the capability of propagating sensitive impressions to the spinal 

 marrow, and of re-acting by twitchings. Even the end of 

 the tail has still perception ; nay, this power is as much ele- 

 vated by the division of the spinal marrow, as in frogs which 

 have been previously narcotized : if a portion of its trunk 

 after being cut off' be only very lightly touched, it always 

 contracts, and this continues for hours. But this interesting 

 phaenomenon is only shown when the spinal marrow is still con- 

 tained in the separated piece, and not in whole limbs separated 

 from the trunk and not containing any spinal marrow. These 

 interesting facts I observed several years ago, 1830, when with 

 Herr Jorclan 1 was investigating the poison of the cutaneous 

 glands in the spotted lizard. It results from this that the ge- 

 neral twitchings which take place in animals on touching par- 

 ticular parts, do not result Irom communication of sensorial 

 and motor nervous filaments, but that the spinal marrow is 

 the connecting medium between the sensorial-centripetal and 

 the motor-centrifugal excitement. 



*' The phaenomenon of general twitchings after local percep- 

 tions is therefore also independent of the sympathetic nerve, 

 and is induced by an irritation of the spinal marrow, by which 

 every purely local sensorial-centripetal excitement propagates 

 itself to the whole spinal marrow and brain, and from thence 

 of necessity excites all motor fibres. But this irritable con- 

 dition is excited by the following causes : 



" 1. In many animals by the mere division and injury of 

 the spinal marrow. Thus tortoises move after the head is cut 

 off*, whenever they are touched; and young birds move on 

 being touched immediately after decapitation, as do also all 

 parts of the cut-off* trunk in the lizard. 



'* 2. Further, the spinal marrow is irritated to this degree 

 in the first stage of narcotic poisoning in frogs, as well as in 

 mammalia, which move after poisoning with nux vomica, 

 whenever they are touched. This stage of excitable debility 

 in narcotization almost always precedes the stage of paralytic 

 debility. 



" 3. Other causes also, which debilitate the brain and spinal 



