KUPTURES OF THE HEAET. 359 



injecting fluid into it. He summed up : 'The results of these 

 experiments, in the way of illustration, as applied to the case 

 with a view to which they were instituted, are in no wise 

 clear and satisfactory. Considering them generally, they are 

 perhaps less uniform than might have been expected, and 

 hardly favourable to any general conclusion being deduced 

 from them, excepting indeed the following: Istly, That the 

 power of resistance possessed by the heart and large vessels, 

 independent of any vital properties of endurance peculiar to 

 them, is enormous; and, 2ndly, That there is much variation 

 in point of strength in the same parts in different instances/ 

 Not much more conclusive, though certainly free from the 

 objection which always attaches to experiments upon dead 

 animals performed with a view to illustrate occurrences in 

 living ones, were the experiments of Chaussier (Portal's 

 Memoria cit.) He found that when the trunk of the aorta is 

 ligatured in an animal, the left auricle and ventricle burst ; 

 but if the ligature be applied to the trunk of the pulmonary 

 artery, the right ventricle and auricle dilate considerably, the 

 contractions of the heart redouble, but its walls do not rup- 

 ture,' Admitting the fact, its bearing is doubtful, if any. 

 The causes which commonly produce traumatic ruptures of 

 the heart, cannot operate so as to occlude the great arterial 

 trunks, particularly the aortic; and if they did, rupture of 

 the heart should more frequently be noted in the left side, 

 whereas the reverse is in fact the case. 



" More to the point is a very interesting observation by my 

 brother John. While prosecuting his investigations in com- 

 parative pathology in the slaughter-houses of Ferrara, in the 

 spring of last year, his attention was particularly attracted 

 by several cases of rupture of the vena azygos, which he asso- 

 ciated with the manner in which the animals were killed 

 division of the spinal cord by thrusting a knife into the 



