85 



The significance of some of these results of experimental 

 physiology does not seem to have been fully realized in 

 relation to their bearing on the human subject. In this con- 

 nexion the conrincing researches of W. T. Porter^* (1896), 

 Baumgarten=^« (1899), Miller and Matthews^"* (1909), and 

 F. M. Smith*^ (1918) are specially relevant. Numerous 

 observations show that in presence of the defective blood 

 supply following ligation the abnormal conditions that 

 develop in the anaemic areas can not only predispose and 

 lead up — often after months — ^to fibrillation, either during 

 muscular exertion or during rest, but that the abrupt onset 

 of fatal fibrillation may come without preceding signs of 

 cardiac failure, as tested by exercise, or without immediately 

 premonitory evidences of cardiac disturbance in the shape of 

 extra-systolic irregularities, tachycardia, etc. Thus fibrilla- 

 tion can occur without apparent exciting cause and quite 

 apart from the sequence commonly observed — extra-systoles, 

 tachycardia, and fibrillation — when death suddenly comes as 

 an early event after coronary ligation. In other cases, at a 

 much later time, disturbances of rhythm and evidences of 

 heart failure present themselves, increasing in intensity and 

 eventuating in fibrillation. Or temporary irregularities 

 may have developed at varying periods after ligation — to 

 give place later to regular I'hythm, and then after weeks or 

 months to fibrillation and sudden death. 



Sudden and Unexpected Death during Best. 



The difficulty of explanation of such deaths has long been 

 felt, in the absence of recognized conditions (effort and 

 excitement) tending to make an extra call on the heart and 

 of such powerful afferent excitation as might be assumed 

 to be provocative of reflex inhibition of intensity and dura- 

 tion sufficient to be fatal. Recourse has constantly been had 

 to the verdict of " failure of the heart's action," though the 

 sudden collapse in cardiac efficiency remains unaccounted 

 for, post-mortem examination often affording no explana- 

 tion of the abrupt ending of life. Sir Clifford Allbutt,^^ 

 while suggesting vagus inhibition as a mode of death during 

 anginal attacks, writes with regard to the class of deaths 

 now under consideration — during conditions of rest, apart 

 from anginal attacks, and where no exciting cause is 

 apparent : 



" But the riddle, which I have done so little to read, is the 

 frequent suddenness of death in one who, having scarcely known 

 illness, expires under no extraordinary effort; or in the peace of 

 his own bed or chair passes silently away. The reading of this 

 riddle is not yet." 



In this relationship the facts that have been stated with 

 regard to the more or less remote effects of experimental 

 interference with the coronary blood supply by ligation of 

 a branch are obviously of profound significance, showing 

 as they do that ordinary life can go on for prolonged periods 

 (months), either with or without signs of cardiac distur- 

 bance, until a sudden ending comes by fibrillation, sometimes 



