252 Epidemics. 



whole, resolves itself simply, in its first and second stages, 

 into slow and spreading congestion of the lungs, and an 

 irritable heart ; and, in the third stage, into pure chronic 

 pneumonia, with or without pleuritic effusion, and more 

 rarely effusion into the pericardium. It appears to be 

 identical with the chronic catarrhal pneumonia of Hedinger 

 (B. and F., January, 1870, p. 116). 



On all hands, the diminished power of the heart's impulse 

 in propelling the blood through the system powerfully con- 

 tributes to a general abatement of all the more acute and 

 inflammatory conditions. 



It will be said that the leading epidemic of the present 

 century cholera and the leading defect upon a special 

 organ, are both placed under contribution as selecting the 

 heart as the chief centre from whence evils spreading to 

 other organs are powerfully aided and sustained. This is 

 quite true, but why a fungiferous poison in the vegetable 

 kingdom (the supposed material poison in cholera) should 

 acquire a specific action upon the heart, more than any 

 other organ, appears to arise from the very impressible 

 nature of the lower forms of life to undergo changes in 

 their development and properties from slight difference 

 in the kind of nutriment upon which they feed ; and if 

 the direct nutriment by which they grow occasions such 

 changes in their form and size, etc., is it difficult to con- 

 ceive that some great and general agent, or force, which 

 directs and gives form to disease, should not also give to 

 fungi, when this force is passing over the earth in certain 

 waves, a new power by slightly regulating their molecular 

 changes, whilst feeding upon certain kinds of aliment to wit, 

 decaying animal matter and decaying vegetable matter and 

 in this manner each, according to the aliment upon which it 

 feeds, presenting different properties when playing upon the 

 human economy as a blood parasite one tending most to 



