266 



Mr. G. J. Romanes on 



[Jan. 16, 



5. The contraction of nerve-corpuscles, which, being much more 

 marked between their branches, gave them a scalloped appearance. 

 Vacuoles were formed within them, and in the spaces formed by their 

 retraction, and by the retraction of surrounding parts. 



6. In some places rupture of nervous tissue was observed. 



7. In longitudinal sections nerve-fibres were found flattened and 

 varicose, the flattening resembling that described by Elischer in fibres 

 of median nerve in chorea. 



Conclusions. — 1. That, in young dogs, the protoplasmic constituent 

 of the grey matter contracts en masse under the influence of strong 

 faradaic currents. 



2. That it contracts unequally and irregularly by reason of its un- 

 equal and irregular sectional area, causing thereby condensations at 

 certain points — notably in the anterior horns and around the central 

 canal — and rarefaction at others — notably in the middle of each 

 crescent ; such rarefaction going on sometimes to rupture of tissues. 



3. That nerve- corpuscles contract in various degrees according to 

 the strength and duration of currents, and that while they tend in 

 contraction to become spherical they also tend to become vacuolated. 



4. That the vessels are in some places strongly contracted and 

 empty ; in others dilated and filled with blood clot, having the appear- 

 ance of embolus. 



5. That the appearances correspond so decidedly with appearances 

 in chorea and tetanus as to give ground for the supposition that con- 

 tractions, such as are produced by electricity, do actually occur during 

 life under the effect of nervous shock, and may be phenomena causal 

 or associate of disease. 



V. "Concluding Observations on the Locomotor System of 

 Medusae." By George J. Romanes, M.A., F.L.S. Com- 

 municated by Professor Huxley, Sec. R.S. Received De- 

 cember 30, 1878. 



(Abstract.) 



The principal bulk of the paper is devoted to a full consideration of 

 numerous facts and inferences relating to the phenomena of what the 

 author terms " artificial rhythm." Some of these facts have already 

 been published in abstract in the " Proceedings of the Royal 

 Society" (vol. xxv), and to explain those which have not been 

 published would involve more space than it is here desirable to allow. 

 The tendency of the whole research on artificial rhythm, as produced 

 in various species of Medusae, is to show that the natural rhythm of 

 these animals (and so probably of ganglio-muscular tissues in general) 

 is due, not exclusively to the intermittent nature of the ganglionic 



