CENTRAL NERVOUS SYSTEM. 



651 



panying figures, is simply this : that an extra stimulus caused by the condi- 

 tions just enumerated and sent into the central system, often at one very def- 



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FIG. 171. A series of small figures showing various reinforcements of the knee-kick (Lombard) ; curves 

 constructed from the original records. Numbers at the left indicate the height of kick in millimeters : A, 

 subject asleep, when the curve is lowest ; * reinforcement after being called ; B, first part of curve low ; 

 * reinforcement in the knee-kick on repeating Browning's poem, " How they brought the good news from 

 Ghent to Aix." C, * reinforcement as the result of talking ; D, * reinforcement due to itching of the ear; 

 E, * reinforcement due to the crying of a child in the next room ; F, * reinforcement due to swallowing. 



inite point, does not limit its influence to that immediate portion of the system, 

 but in all these cases the nerve-cells located in that portion of the spinal 



