12 WILLIAM PATTEN. 



a week or ten days after, vigorous movements on both 

 sides were produced by rubbing pieces of clam well over 

 the mandibles. As might be supposed from experiment No. 4, 

 the movements were especially well marked when the clam was 

 rubbed over the under side of the inner mandibles, but they 

 could be produced when only the outer part of the mandibles 

 was touched. After the reflex had been once restored 

 it required but little more stimulation to start the 

 reflex in the shaved mandibles than it did before 

 in the unshaved ones, (c) Now^ if we cut oflF the inner 

 mandible of the right side the reflex on that side will again 

 be suspended, but it can be once more partially restored by 

 (d) cutting off the inner mandibles of the other side. The 

 restored powers are each time feebler than before, but nothing 

 short of amputating both inner and outer mandibles will 

 completely and permanently destroy the reflex. The feeble 

 movements caused by stimulation after the spines and the 

 inner mandibles have been removed are produced by scattered 

 gustatory buds distributed between the spines over the anterior 

 face of the mandibles. The reflex chewing movements in one 

 appendage, therefore, are not lost in proportion to the destruc- 

 tion of sense organs in it, but depend rather on the relation 

 between the number of sense organs retained in it and those in 

 the other appendages. Hence if the reflex in one appendage is 

 suspended by destruction of a certain number of sense organs, 

 it may be partially restored by reducing the number of sense 

 organs in the other appendages in a like degree. In other 

 words, the reflex impulse enters the widest door. 



The reflex flows more readily along the most recently used 

 lines, as shown by the following experiment : — If mandible a 

 be slightly stimulated with food, whether enough to produce 

 reflex movements or not, subsequent (say five minutes after) 

 stimulation of all the mandibles to the same extent will pro- 

 duce reflex movement in mandible a first, and afterwards 

 feebler movements in all the others. 



B. Structure of the Gustatory Organs of the Man- 



