l6 QUATERCENTENARY STUDIES IN PATHOLOGY 



Of course we cannot claim to have shown definitely any connection 

 between this type of irregularity in the dog's heart and that in the case 

 described. At the same time there exist similarities between them, and 

 the sudden onset of the irregularity in each suggests a common cause ; 

 in the dog the lesion acts through the central nervous system, and the 

 history of the patient suggests that here also the irregularity was of 

 central origin. We had hoped to have the opportunity of continuing 

 the investigation in other cases of irregular heart, but as circumstances 

 preclude our working further together, we have decided to put this 

 imperfect investigation on record, in the hope that others may be 

 interested in the suggestion made, and may be able to prove or disprove 

 its correctness. 



Summary. 



A case of paroxysmal arhythmia, with marked acceleration of the 

 heart, is described, and it is shown that the irregularity is due to irregular 

 discharge of impulses and not to defects in the contraction of the 

 ventricle, which appears to respond to the impulses received. A similar 

 form of irregularity in the dog's heart is described, and it is shown that 

 this is due to the ventricles receiving irregular stimuli from the auricle, 

 which is in a state of fibrillation. This form of arhythmia is shown to 

 occur in the dog occasionally from peripheral irritation, and it is probable 

 that this gives rise to reflex inhibition of the vagus centre, which, acting 

 on an abnormal heart, causes auricular fibrillation. The suggestion is 

 made that in the patient described, and in other cases of paroxysmal 

 arhythmia, the condition is due to auricular fibrillation, possibly from 

 inhibition of the vagus centre. 



(no) 



