MALFORMATIONS OF THE BULBUS CORDIS 19 



Further, I have been able to collect nine cases exactly similar to this, 

 but the interpretation of the cause of the condition is rendered difficult 

 by the fact that in every case endocarditis was present. The ostium 

 bulbi on the right side of the heart, when it persists, is specially liable to 

 become the site of an endocardial lesion ; it seems to me that this 

 explanation may be also employed for the left side of the heart ; a 

 constriction such as is caused by a persistent part of the bulbus cordis 

 is especially liable to become the site of endocarditis. Further, the 

 constriction which is seen in this and in similar cases, occurs at the 

 position and in the form which one would expect from a persistent 

 remnant of a bulbus cordis on the left side of the heart. 



It would carry this paper beyond its proper compass were I to 

 describe cases in which the bulbus cordis has atrophied round the 

 pulmonary artery, and not only persisted but attained a great muscular 

 development round the origin of the aorta ; in this form of maldevelop- 

 ment is to be found the explanation of the not uncommon condition of 

 transposition in the origin of the aorta and pulmonary artery. Nor do 

 I intend to deal with that form of atrophy of the aortic part of the 

 bulbus which leads to complete aortic stenosis, so common in Russia 

 and so rare in England. I have gone far enough to show that the theory 

 of foetal endocarditis cannot account for the various forms of congenital 

 lesion which I have shown to occur in the heart, and the causation of 

 which has to be sought for in the first month of foetal development. 

 Further, these malformations cannot be accounted for except on the 

 hypothesis that the bulbus cordis forms an intrinsic part of the mam- 

 malian heart ; the bulbus is not completely absent in the mammalian 

 heart, as has been the current opinion up to the present. That it does 

 exist in the form described we have as evidence not only its persistence 

 as the result of maldevelopment, but also the facts of embryology and 

 comparative anatomy. 



To render the evidence more complete, that these lesions are not the 

 result of foetal endocarditis, but of some agent, the nature of which we 

 do not yet know, I propose to give in this paragraph the results of the 

 examination of the heart in a group of 23 malformed human foetuses 

 and infants. The malformations which these foetuses and infants 

 showed were one or more of the following : anencephaly, hydrocephaly, 

 spina bifida, umbilical hernia, atresia ani, cleft palate, hare-lip and stenosis 



(73) 



