322 THE HEART. 



It was shown by Clendinning that the heart continued to increase in weight up to 

 an advanced period of life, but at a comparatively slower rate subsequently to the 

 age of twenty-nine years. Subjoined is a tabular statement of some of the average 

 results derived from the observations of these authors. 



CLENDINNING. REID. PEACOCK. 



Weight in oz. Weight in oz. and drachms. 



Age in years. Males. Females. Age in years. Males. Females. Males. Females. 



15 to 29 ... 8| ... 81 16 to 20 ... 8 10 ... 6 13 8 2 ... 8 1| 



30 50 ... 91 ... 81 20 30 ... 10 4 ... 8 9 01 ... 8 10} 



50 60 ... 101 ... 8 30 40 ... 10 8 ... 9 3 97 ... 8 13| 



60+ ... 101 ... 8 40 50 ... 11 7 ... 9 8 8 11 ... 9 3 



50 60 ... 11 10 ... 9 14 9 12 ... 9 71 



60 70 ... 12 6 ... 9 5 10 13| ... 7 



70 (- ... 12 6 ... 9 6 



Entirely in accordance with these observations upon the increase of the heart's 

 weight according to age, it has been found by Bizot that this organ continues to enlarge 

 in all its dimensions as life advances, viz., in the length, breadth, and thickness 

 of its walls. The greatest increase was detected in the substance of the left ventricle, 

 and the ventricular septum. (Reid, in the Lond. and Edin. Monthly Journal of Med. 

 Science, April, 1843; T. B. Peacock, in the same journal, in 1846, and reprinted 

 separately, with additional observations, in 1854 ; Clendinning, in the Medic. Chir. 

 Transact., 1838 ; Bizot, M6m. de la Soc. M6dic. d'Observation de Paris, torn. i. 

 p. 262. 1836.) 



Capacity of the auricles and ventricles. To determine with precision the absolute 

 and relative capacities of the four cavities of the heart, as they exist during life, is 

 impossible ; and their capacity is so much influenced by their different states of 

 distension, and also by the different degrees of contraction of their muscular walls at 

 the moment of death, that no constant numerical relation in this respect can be 

 looked for between them. Hence the most opposite statements prevail, especially 

 with regard to the size of the ventricular cavities. 



The auricles are generally admitted to be rather less capacious than the ventricles. 

 The right auricle is also said to be larger than the left, in the proportion of 5 to 4. 

 (Cruveilhier.) 



The capacity of the left ventricle has been stated by different anatomists as 

 variously as at 1| fluid ounces and 4 oz. ; it probably does not exceed 2 oz. 



The right ventricle is asserted by some to be larger than the left ; by others (Lower, 

 Sabatier, Andral) the two are stated to have an equal capacity ; Cruveilhier, j udging from 

 the effect of injections, has found the left to be the larger of the two. In the ordinary 

 modes of death, the right ventricle is always found more capacious than the left, 

 which is probably owing to its being distended with blood, in consequence of the 

 cessation of the circulation through the lungs : the left ventricle, on the other hand, 

 is found nearly empty, and thus becomes more fully contracted. There are reasons 

 for believing, however, that during life scarcely any difference of capacity exists 

 between the two cavities. 



Size of the ventricular openings. The right auriculo-ventricular opening, and the 

 orifice of the pulmonary artery, are both found to be somewhat larger after death 

 than the corresponding openings on the left side of the heart. Their circumference 

 is thus stated by Bouillaud. (Traite des Malad. du Coeur, torn. i. p. 52. Paris, 1835.) 



Inches and Lines. 

 Max. Med. Min. 



Auriculo-ventricular orificesj^ ; J ^ * J 



Arterial orifices j Right (Pulmonary) 210 27 26 

 ' | Left (Aortic) 28 28 24 



According to Peacock's most recent observations, the following (omitting the 



