88 Charles W. Hargitt. 



roslon patches, similar to those mentioned in the earher portion 

 of this paper and comparable in general aspects to cases men- 

 tioned by Uexkiill, it was found that after all the rhopalia had 

 been removed the specimen yet exhibited certain convulsive con- 

 tractions which at times simulated an irregular rhythm. I there- 

 fore undertook to repeat several of this observer's experiments 

 as to the effects of certain chemical stimuli, specially that of com- 

 mon salt, NaCl. Small crystals of this salt were carefully placed 

 on definite parts of the sub-umbrellar musculature, and I was able 

 thereby to confirm in the main his results. There was a very evi- 

 dent white coloration of the adjacent tissues, and this was followed 

 by a more or less definite, though somewhat irregular, rhythmic 

 contraction of the umbrella which continued for perhaps five 

 minutes. The experiment was repeated several times and upon 

 different specimens and with usually similar results, though dif- 

 fering as to vigor or continuity. 



Uexkiill had concluded that the recovery of a similar rhythm 

 In specimens upon which he had experimented by excising the 

 rhopalia was due, not to any direct restoration of nervous or 

 other normal equilibrium, but to certain pathologic conditions 

 which had Intruded themselves, and among which he was spe- 

 cially Impressed by these corrosion abscesses or disease patches, 

 to which reference has been made. Doubting whether an agent 

 of this sort, affecting particularly the exumbrella, could have any 

 very definite Importance as a center of stimulus, It occurred to me 

 to vary the experiment by applying the salt to the exumbrellar 

 region Instead of the musculature of the sub-umbrella, and though 

 variously repeated the results were uniformly negative In char- 

 acter, no conclusive responses of any sort being obtained. Nor 

 was there observed any of the whitening effects which were so 

 evident In the previous experiments. We may conclude, it seems 

 to me, that the effects produced by the salt in arousing a simulated 

 rhythm of contraction was due to the direct action of the sub- 

 stance on the musculature Itself, and not to any general effect 

 produced upon the coordinating centers of the medusa. These 

 stimulating effects of sodium chloride upon muscular tissue are too 

 well known to call for any special mention In this connection. 



