n 4 



-systems of which it consists, for the purpose of observing 

 how far, or to what extent, they are subject to the influence 

 of heredity, and how far this influence bears upon indi- 

 viduality as affecting disease. First, with regard to 



Diseases of the Circulatory System. Are these, or any 

 of them, subject to heredity? Before this question is 

 answered, it should be carefully borne in mind that the 

 whole subject of disease tendencies and immunities in 

 connection with heredity has been before the public and 

 the profession for comparatively few years, and if I were 

 to sum up our present knowledge of the heredity of these 

 diseases, and reply in the negative, I fear my answer would 

 savour more of ignorance than of scientific exactitude; 

 for to say that things are not, when they may be, is surely 

 presumptive of self-contented ignorance, and in direct 

 opposition to the spirit of scientific inquiry and progress. 

 Thus while circumstances may compel us to confess our 

 ignorance, science is ever beckoning us on, and promising 

 us increased knowledge and deeper lore if we only follow 

 her aright. Synthetically we find man's physical, mental, 

 and moral nature not only subject to, but to a great extent 

 dependent upon heredity, and analytically we find all his 

 organs and tissues subject to the same influence; and if 

 such is the case in health, why should it not be so in disease 

 since diseases are simply new phases of the vital manifes- 

 tations, partaking of the character of either functional 

 derangement, or organic or textural degeneracy ? And if so 

 in some diseases, as it undoubtedly is, why not in all, as they 

 are merely deranged functions, or organic or textural 

 degenerations of organs or tissues which are unquestionably 

 inherited? It is admitted that man, in all his parts and 

 functions, is the result of heredity, with the exception of the 



