90 Milton Landowne 



pressure component of left ventricular work is evidence that, 

 despite the lesser requirement for blood, there is a reduction in 

 the effective reserve of the left heart as a muscle pump. 



The foregoing has been painted with a wide brush to reflect 

 trends which are demonstrable among groups of ostensibly 

 well people. It is offered to illustrate some of the experimental 

 and statistical methods which we have applied, and the inter- 

 pretations which endeavour to give us some insight into the 

 logistics of the circulation. In presenting these examples of 

 studies in human cardiovascular physiology, I may have 

 selected a field where dissociation of the progress of years 

 from a high and increasing degree of pathology is currently 

 most difficult. Perhaps I have deliberately laid emphasis on 

 this because I believe cognizance of the limitations, as well as 

 the advantages of the clinical approach, is an asset to inquiry. 

 For the restricted area of organ function study, this report has 

 been an effort to illustrate the reasoning which motivates 

 specific and quasi-specific methods of study. 



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