DETERMINATION OF SIZE OF HEART BY X-RAYS 475 



diastolic volumes ( + 2| to — 2| per cent divergence), the number 

 (27) of those which show a volume above what is assumed to be 

 the normal diastolic volume is greater than the number (15) 

 which show a volume smaller than the normal diastolic volume. 

 This is what we should expect from the conditions of the hearts 

 studied. 



The post-mortem condition of the heart has been studied by 

 several investigators including Mac William ('01) and Roth- 

 berger ('04). At the time of death the heart is in diastole. The 

 amount of blood in the heart depends on the general circulatory 

 conditions at this time. After death there is a tonic contraction 

 of the heart followed by a rigor mortis contraction. The post- 

 mortem contraction of the heart is usually much greater in in- 

 dividuals in whom the respiration stops before the circulation 

 than in those in whom heart failure is a primary cause of death. 

 The postmortem contraction is follow^ed by a subsequent dila- 

 tation but the extent of this depends to a large extent on the 

 amount of fluid blood under pressure when the dilatation occurs. 



The bodies received at the Anatomical Laboratory at the 

 University of Wisconsin have usually been dead at least a week. 

 As a rule they are embalmed by injecting equal parts of alcohol, 

 glycerine and carbolic acid into the femoral arteries and the 

 thorax is not opened until the body is dissected. In some in- 

 stances we have opened the thorax in order to study the condi- 

 tion of the heart before embalming. As a rule the right atrium 

 is fairly well distended with blood and frequently there is con- 

 siderable blood in the right ventricle. While there is usually 

 some blood in the left atrium this is less apt to be distended than 

 the right atrium. The left ventricle is usually practically empty. 

 When the embalming fluid is injected under a pressure of five 

 or six pounds into the femoral arteries it usually enters the 

 chambers on the left side of the heart and distends them to a 

 moderate degree. The right side of the heart is less affected by 

 the injection than the left side. The embalming fluid is usually 

 followed by a shellac and Prussian blue arterial injection mass 

 which also usually partially fills the chambers in the left side of 

 the heart but not those on the right side. We have not meas- 



