Licence: Public Domain Mark
Credit: Heart / by John Reid. Source: Wellcome Collection.
Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.
12/46 (page 12)
![as stated by Cloquet and Cruveilliier, is as 5 to 4. Tlie right ventricle is generally found larger than the left after death. This difference has been very variously estimated by different anatomists. Some, as VVinslow, Senac, Ilaller, Lieutaud,* and Boyer, have maintained that tiiere is a mixrked disparity between the ca]ja- cities of the two cavities, while Meckel, Laennec, Bouillaud, Portal, and others be- lieved that this difference is to a smaller extent. Lower was the first to maintain that both ventricles are of equal size. Sabatier, Andral, and others have supported this opinion ; while Cruveilhierf states that he has satisfied himself, from comparative injections of the two cavities, that the left ventricle is a little larger than the right. Gordon has occasionally found both ventricles of equal size, and Portal has seen them of the same size in young persons. Santorini and Michelattus believed that, though the capacity of the left ventricle appears a little smaller than that of the right, yet that the superior force of the left auricle over the right dilates the left ventricle sufficiently to render it equal to the right. The majority of anatomists, however, have always maintained that the capacity of the right ventricle is greater than that of the left, and have adduced the following arguments in support of this opinion: 1, that the right auricle, right auriculo-ventricular orifice, and origin of the pulmonary artery are larger than the auricle and corresponding orifices of the opposite side: 2, that when both ventricles have been filled with water, mercury, or wax, more of these substances is found contained widiin the right than the left: 3, the experi- ment of LegalloisJ shew that when an animal is bled to death, this disparity between the size of the ventricles is still found. Those who maintain that the capacity of these two cavities is equal do so on the following grounds:—1, that as the walls of the right ventricle are weaker than those of the left, when the same force is used in injecting both, the right must, as a matter of course, be more dilated than the left. 2. Sabatier ingeniously suggested that, as during the last moments of life the passage of the blood from the right side of the heart is generally impeded, producing engorgement of that side, while the left side was generally em])ty, this might account for the greater size of the right ventricle. 3. Sabatier and Weiss§ maintained that in those cases where the kind of death was such that the right side of the heart could not be en- gorged as in fatal haemorrhage, no difference between the capacity of the two sides could * Memoires dc I'Academic Roy. des Sciences, t. viii. p. 561, 1754. Lieutaud's authority is some- times quoted in support of tlie opinion that these cavities are of equal capacity. t Anatomic Descriptive, t. iii. t Dictionnaire des Sciences Med. t. v. p. 436. These experiments were performed upon dogs, cats, guinea-pigs, and rabbits. § Dc dextro cordis ventriculo post mortem am- pliore. be observed. 4. The experiments of Sabatier, in which, after tying the aorta and producing engorgement of the left side of the heart, while the right side was emptied by a wound made into the vena cava or pulmonary artery, the left ventricle was found to be of ijreater capacity than the right. M. Bizot maintains that the capacity of the ventricles goes on increasing from youth up to old age; and that this, contrary to the opinion of Beclard, is not so rapid in old age as in the earlier periods of life. The following are a. few of M. Bizot's measure- ments:— Left ventricle, male. Age. Length. Breadth. 1 to 4 years 20 lines. 31 lines. 50 to 79 years 36 „ 56§ „ Average from 15 to J 79 years i 8t» ^^#1 „ Left ventricle, female. 1 to 4 years 18.^ lines. 29| lines. 50 to 79 years 31 „ 49i „ Average from 15 to ) „ 89 years ^ » '^Oro » Right ventricle, mule. 1 to 4 years 20i lines. 47| lines, 50 to 79 years.... 37^ „ 87 „ Average from 15 to ^ ^ 79 years ^ -^'si » ^-^m » Right ventricle, female. 1 to 4 years ..... 18| lines. 44| lines. 50 to 79 years 35„ 76 „ Average from 15 to ^ . 89 years S Every one must confess that the right ven- tricle is generally found larger after a natural death in the human subject than the left; and it appears exceedingly probable that these two cavities, in the healthy state of the organ, contain different quantities of blood during life. As the capacity of the auricles is rather smaller than that of the ventricles, it may be asked how can the auricles furnish blood sufficient to distend the ventricles? We shall afterwards more particularly explain that the blood passes from the auricles into the ven- tricles at two different times during the interval betvveen each contraction, viz. at the moment of its relaxation, and again during the con- traction of the auricles. Various attempts have been made by those who maintain that the right side of the heart is larger than the left, to explain how the equilibrium of the circulation can be maintained. Helvetius* supposed that this could be accounted for by the diminution which the blood sutfeied in passing through the lungs; and in proof of this he erroneously maintained that the pulmonary arteries were larger than the pul- monary veins. Legallois believed that this could be explained (as appears very probable) by the greater size of the right auriculo-ven- tricular opening, allowing a greater reflux of blood back again into the auricle, during the systole of the ventricles. • Memoire de I'Acad. Roy. 1718, p. 285.](https://iiif.wellcomecollection.org/image/b21908503_0014.jp2/full/800%2C/0/default.jpg)
