u8 



or less, particularly susceptible ; and in other cases the cir- 

 cumstances of their life-history have either developed in- 

 herited predispositions, or originated them de novo, to be 

 passed on to future generations. Let us take, as an example 

 of the inflammatory causes, acute diptheritic or subacute 

 verrucose endocarditis. What are the facts known as 

 to their etiology? Simply that one or both are usually 

 associated with rheumatic arthritis, childbirth, or pregnancy, 

 and occasionally with the acute exanthematous diseases. 

 How many thousands of such conditions occur without the 

 slightest implication of the endocardium at all ? And why 

 should pericarditis be far more frequently associated with the 

 gonorrhceal form of rheumatism than the endocardial form 

 of inflammation ? Why, also, with regard to prognosis in 

 the chronic and sclerotic form, are as many individual pecu- 

 liarities produced by the diseases of the different valves as 

 there are individuals affected ? Is the disease itself different 

 in every individual ? Assuredly not ; but the real reason is 

 that while the individuality of tissue in some predisposes 

 them to such affections, in the majority of others it renders 

 them insusceptible. So also with regard to degenerative 

 changes in the cardiac or vascular tissues, whether fatty, cal- 

 careous, amyloid, tubercular, or syphilitic. We shall in every 

 case find the result originating either in hereditary or acquired 

 predisposition, or in both combined, and in every case the 

 proportionate action of these factors is as different as are its 

 results in different individuals. For hundreds who have 

 suffered from heart affections of various kinds, and in different 

 degrees, there are thousands and thousands who, during 

 long lives, have neither experienced inconvenience nor 

 derangement of any kind in connection with their circulatory 

 system, and this exemption has been entirely owing to the 



