282 



Mr. Graham Brown. 



[Apr. 11, 



f 



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u 







vn \ 



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y 5 

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2 r 6 a x // /, 



--i _ o J - /> C /•/-.. 2?__. . A..... „ o~---ivc,„ O 

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Fig. 2. 





Experiment 30, 31.3.11. — A continuation of the last figure. Two reactions. 



In the first of these (e) the contralateral stimulus is applied for some time (about six seconds) 

 before the ipsilateral stimulus is added. They then run together for about eight or nine seconds. 

 During this time the extensor movements — which before were maintained— are rhythmic. 



In the second reaction (/) the ipsilateral stimulus is applied earlier, but is taken off again 

 before the termination of the contralateral. Here the extensor contraction is maintained before 

 the commencement and after the termination of the ipsilateral stimulus, but when both stimuli 

 run together it is rhythmic. 



V. Other Forms of Rhythmic Movements. 



The author has previously described movements of progression which occur 

 under narcosis in the rabbit.* Similar movements have been seen in the 

 guinea-pig under suitable circumstances. These in their rhythm seem to 

 bear the simple relationship of 1 : 4 to the rhythm of the " beats " of the 

 scratching movements which occur under narcosis in the guinea-pig. In the 

 rabbit the relationship seems to be commonly 1 : 2. 



Similar movements also occur in the cat. These are of additional interest, 

 in that they may be observed in the same individuals from which records of 

 the other movements of progression, provoked in other ways — e.g., reflex, 

 central on cutting spinal cord, etc. — were subsequently obtained. 



* 1 Quart. Journ. of Exp. Physiol.,' 1911, vol. 4, p. 151. 



