( lf^5 ) 



frozen solid ovoi' liquid liydrof2;en. Il is (piilo prohiiltlc that llic tern- 

 pcraJiirc of thai solid piiasc lay niiich lower than tho tiiio iiicltiiiii' 

 point of oxvincn. 



We .gratefully acknowledge oui' indebtedness to Mr. G. Hoi.st, who 

 was kind enough to undertake the measurement and calculation of 

 the above temperatures. 



Physiology. — ''On, (lllj'erinit r(f(//is ('ffCf-ts /t/Hin th(' hcftrf /i/ri'st/\jaf,-(/ 

 hji means of ('l(X'troc(ir<//'o(/r'/i)/ii/.^^ \\\ W. Eintiiovkn aud 



J. H. WlEKlNGA. 



A nuud)er of electrocardiograms give evidence, that dill'erenl effects 

 on the heart action can be obtained by vagus stimulation in dogs. 

 Not oidy the frequency of the heart beats is diminished by stimulation of 

 a vagus nerve, but at the same time the auricle contractions are 

 weakened and often modified. 



There can be produced a partial block, i.e. that not every auricle 

 contraction is followed l)y a ventricle one, as in normal circumstances, 

 bnt that two or more auricle contractions precede a single ventricle 

 systole. 



There can appear a com[»lete block, auj-icies and venti'icles beating 

 in their own rhythm. 



The conduction through the right branch of the auricnlo-ventiicidar 

 bundle can be impeded, effecting an atypical systole. In these circum- 

 stances the ventricle electrogram shows the shape of the afy|)ical 

 electrograms, which are produced by stimulation of the left biaiich of 

 the bundle. 



Il also liap|)ens, that the conduction through the left branch of 

 the bundle is impeded, atypical electrocardiograms being recorded 

 of the opposite form. 



Theie finally can be produced imi)ediments that either affect one 

 of the branches of the bundle partially or that are not purely i.solated 

 in I hat branch. In these cases there appear ventricle electrograms, 

 the shape of which differs from those described. 



The different effects of \agus stimulation are explained in the 

 sinq)lest way by assuming, that there are various knots of fibres in 

 the trunk of that nerve, some of which being connected with tiie 

 aui-icles, some others with ihe node of Aschoff-T\\\ ak \ ami again 

 others with each l)ranch of the bundle. If .some fibres react more 

 strongly than other fibres u|)on a stimulus, the heai-t action will 

 be modified in a special way, e\'ery knot of fibres producing its 

 own peculiar effect. 



