Chap.X.] transmission OP MOTOR IMPULSE. 195 



of the discs of four leaves, and cubes of the same size at the 

 proximal or distal end of four other leaves. Now, when 

 these two sets of leaves were compared after an interval of 

 24 hrs., they presented a striking difFerence. Those having 

 the cubes on one side were very slightly affected on the op- 

 posite side; whereas those with the cubes at either end had 

 almost every tentacle at the opposite end, even the marginal 

 ones, closely inflected. After 48 hrs. the contrast in the 

 state of the two sets was still great ; yet those with the meat 

 on one side now had their discal and submarginal tentacles 

 on the opposite side somewhat inflected, this being due to 

 the large size of the cubes. Finally we may conclude from 

 these thirty-five experiments, not to mention the six or seven 

 previous ones, that the motor impulse is transmitted from 

 any single gland or small group of glands through the blade 

 to the other tentacles more readily and effectually in a longi- 

 tudinal than in a transverse direction. 



As long as the glands remain excited, and this may last 

 for many days, even for eleven, as when in contact with 

 phosphate of lime, they continue to transmit a motor im- 

 pulse to the basal and bending parts of their own pedicels, 

 for otherwise they would re-expand. The great difference in 

 the length of time during which tentacles remain inflected 

 over inorganic objects, and over objects of the same size con- 

 taining soluble nitrogenous matter, proves the same fact. 

 But the intensity of the impulse transmitted from an excited 

 gland, which has begun to pour forth its acid secretion, and is 

 at the same time absorbing, seems to be very small compared 

 with that which it transmits when first excited. Thus, when 

 moderately large bits of meat were placed on one side of the 

 disc, and the discal and submarginal tentacles on the op- 

 posite side became inflected, so that their glands at last 

 touched the meat and absorbed matter from it, they did not 

 transmit any motor influence to the exterior rows of ten- 

 tacles on the same side, for these never became inflected. 

 If, however, meat had been placed on the glands of these 

 same tentacles before they had begun to secrete copiously 

 and to absorb, they undoubtedly would have affected the ex- 

 terior rows. Nevertheless, when I gave some phosphate of 

 lime, which is a most powerful stimulant, to several sub- 

 marginal tentacles already considerably inflected, but not 

 14 



