70 Royal Society : — 



silicate to carbonate, and then back again to silicate, the only limit to 

 the process would be the satisfying of the mutual affinities of the 

 silica and the basic oxides present. 



May 14.— General Sabine, R.A., Treas. and V.P., in the Chair. 



The following communications were read : — 



"On the Organization of the Brachiopoda." By Albany Han- 

 cock, Esq. 



" On the Placenta of the Elephant." By Professor Richard Owen, 

 F.R.S. &c. 



May 28. — The Lord Wrottesley, President, in the Chair. 



The following communication was read : — 



" On the Cause of the Rhythmic Motion of the Heart," being 

 the Croonian Lecture. By James Paget, Esq., F.R.S. 



The author draws the following conclusions as to the most pro- 

 bable explanation of the rhythmic action of the heart : — 



1. In the Vertebrata it is due to the time-regulated discharges of 

 nerve-force in certain of the ganglia in and near the substance of the 

 heart, by which discharges the muscular walls are excited to con- 

 traction. 



2. Li Invevtebrata, the corresponding pulsatile movements of 

 hearts or vessels are probably independent of nerve-force. 



3. Tlie time-regulated rhythmic action, whether of the nervous 

 centres or of the independent contractile Malls, is due to their nutri- 

 tion being rhythmic, i. e. to their being, in certain periods, by nutri- 

 tive changes of composition, raised, with regulated progress, to a 

 state of instability of composition, in their decline from which they 

 discharge nerve-force, or change their shape, contracting. 



4. The muscular substance of the heart in the Vertebrata, governed 

 in its rhythmic action by appropriate nervous centres, has a 

 rhythmic nutrition of its own, corresponding and coordinate with 

 theirs ; the impairments of its structure during action being repaired 

 in repose. 



5. Rhythmic nutrition is a process in accordance with the general 

 laws of organic life, very many organic processes being composed of 

 timely-regulated alternate action and inaction, or alternate opposite 

 actions, i. e. being rhythmical, with larger or shorter units of time ; 

 and all organic j)rocesses being chronomctric, i. e. ordered according 

 to laws of time as exact, and only as much influenced by external 

 conditions, as are those relating to weight, size, shape, and com- 

 position. 



June 18. — The Lord Wrottesley, President, in the Chair. 



The following communication was read : — 



'* On a new Mode of forming Triethylamine." By A. W. Hofmann, 

 LL.D., F.R.S. 



Researches on the constitution of the nitrogenous organic bases, 

 which I zealously prosecuted some years ago, and the result of 



