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in any individual. For the present I do not consider it 

 necessary to refer to congenital diseases of the heart, 

 such as abnormal positions, congenital narrowness 

 and closure of the ostia of the right side, stenosis and 

 atresia of the pulmonary artery, with closure of the septum, 

 stenosis of the right conus arteriosus, with an opening in 

 the inter-ventricular septum, simple stenosis and atresia of 

 the pulmonary artery with an opening in the ventricular 

 septum, etc., my object being to demonstrate, not that 

 certain diseases of the heart are congenital, but that,, 

 owing to heredity, variability, and accessory circumstances, 

 the organs, vessels, and tissues of every human subject are 

 so variously differentiated by individuality, that they are as 

 variously predisposed to morbid influences, whether of the 

 nature of adynamia, functional derangement, or structural 

 degeneration. Temperament, idiosyncrasy, and diathesis 

 are more or less involved in every question concerning the 

 comparative health of individuals, but we mnst dig down 

 deeper into the origin of constitutions if we are anxious to 

 account for differentiation, which is as universal as humanity 

 itself; and thus we find in the strongest and healthiest, as 

 well as in the weak and invalidish, that in certain organs, 

 vessels, or tissues, there is a predisposition to certain 

 functional or structural alterations, which render their 

 subjects, in varying degrees, liable to morbid influences, 

 referable either to atony or adynamia, impaired functional 

 activity, or structural degeneration. From this view let 

 me now briefly inquire as to how individuality of tissue 

 predisposes to diseases of the heart and circulatory system 

 in general. Weakness, like the term disease, is only a 

 comparative term, and, like the latter, it admits of infinite 

 gradations or degrees. Inherent weakness of the circu- 



