WHAT IS A DISEASE? 235 



valve thus diseased a vegetation may be detached, and may- 

 block an artery in the brain, causing structural damage to the 

 brain, with its characteristic train of symptoms. The term 

 ' embolism of the brain ' has, like other names of structural 

 change, its double meaning. It may mean the presence of 

 the block in the artery, or it may mean this together with the 

 consequent disorganisation of the brain, or it may mean these 

 things together with the paralysis and other symptoms that 

 are evidence of them ; yet, even if the term is understood in 

 the latter sense, embolism of the brain is not the disease, is 

 not the whole disease, from which the patient suffers. His 

 disease is still acute rheumatism, of which the heart disease 

 and the embolism are consequences and parts. If, however, 

 the rheumatism subsides and disappears, leaving the valve of 

 the heart damaged, then this structural damage, plus its 

 s3'mptoms and consequences, becomes the disease from which 

 the patient suffers. We find, therefore, that structural damage 

 to an organ, together with the consequences and symptoms 

 it produces, may constitute a disease, but does not necessarily 

 constitute a disease. 



( To be continued in January 1917) 



