LECTURE III. 



Delivered May 14, 1874. 

 ON STRAIN AND OVER-ACTION OF THE HEART. 



Bt J. M. Da Costa, M.D. 



By the kind invitation of the Trustees of the Toner Lectures 

 I am here to-night to address you on some subject connected 

 with our common profession. The choice is practical]}" left to 

 the speaker ; but if I understand correctly the aim of the emi- 

 nent gentleman whose public spirit has founded these lectures, 

 it is that they shall deal not so much with mere isolated facts, 

 however interesting these may be, but rather with some gene- 

 ral topic, susceptible of being discussed in its broad traits, and 

 the discussion of which should, if possible, contribute to its 

 clearer and fuller vmderstanding. It is acting in this belief 

 that I select a subject admitting of as comprehensive treatment 

 as that of the Production of Diseases of the Heart ; and I am 

 the more tempted to take this as m}' discourse when I remem- 

 ber that the starting point of several of the conclusions I wish 

 to lay before j^ou was in some researches conducted under the 

 auspices of the office over which another trustee of these lec- 

 tures, the Surgeon-General, so ably presides. 



Affections of the heart are very common, and, I think, 

 becoming more so. I have recently seen a statement, the result 

 of statistical inquiries, that there are three kinds of diseases 

 which, in this wide and busy land of ours, are steadily on the 

 increase — insanity, and some affections of the nervous S3^stem ; 

 d^^spepsia; and diseases of the heart. No one engaged in the 

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