276 PHYSIOLOGY OF MUSCLES AM> NT.KYES. 



from nerve-cell t<> nerve-cell, from each of which it 

 can ivpass into a motor fibre. From the length of 

 the time occupied by the reflex irritant, it is to be 

 iiit'i-iTrtl that the transmission of th<' excitement has 

 to meet considerable resistance in the nerve-cells. 

 This resistance naturally increases with the number of 

 nerve-cells to be traversed, so that the transference of 

 a rellex action from a definite sensory fibre to different 

 motor nerve-fibres is not always equally difficult,. and 

 is the more difficult the greater is the number of 

 the cells which lie between the two. All this agrees 

 with the facts found by experiment. It also explains 

 why, by certain influences, not only is the reHex trans- 

 ference rendered easier, but the passage of the excite- 

 ment to the most remote motor fibres is also rendered 

 peculiarly possible. The be-t known case of this is 

 poisoning by strychnine. This so greatly facilitates the 

 reflex transference that the slightest touch on any point 

 of the skin, or even the disturbance caused by a breath, 

 is sufficient to throw all the muscles of the body into 

 violent reflex tetanus. 



As each excitement of a senary jibre which reaches 

 the nerve-centre can give riVe to a conscious sensation, 

 the spread of the excitement vithin the centre must 

 have the same effect as would be the case if u larger 

 number of excitements of several sensory fibres readied 

 the centre simultaneously. This proce^, vhich, IK>\\- 

 c^vr. only occurs in the case of strong excitements, 

 is called ni-i'i'l'ilifi' BenfHtt'uni. Sensation is caused 

 not only by the exeitement of the ner\e-cell directly 



concerned, ),,, a l so ],y the .-ju'ead of tile excitement 



to the other nerve-cells. It may also be spoken of as 

 t lie radiat ion of (he sen-ory irritant, because (he excite- 



