The discovery of the nature of the spleen : from an investigation of the lateral homologies of the liver, stomach, and intestinal canal / by Henry R. Silvester.

  • Silvester, Henry R. (Henry Robert), 1829-1908.
Date:
1870
Catalogue details

Licence: Public Domain Mark

Credit: The discovery of the nature of the spleen : from an investigation of the lateral homologies of the liver, stomach, and intestinal canal / by Henry R. Silvester. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    habits of each race'of animals. We find, in fact, that, if we maj'judge from its size, the importance of the spleen seems to diminish successively from mammalia to birds, then to reptiles, and from them to fishes; and we also find that the liver among the vertebrata, proportionately to the body, becomes progressively larger in passing from the mammal to the fish. For instance, in the mammalia the spleen presents by far its greatest development of struc- ture, and this, no doubt, partly depends upon the greater general completeness and requirements of their organiza- tion. But the liver in mammalia is very much reduced in size, and is more compact and firm than in the lower vertebrata; and may not the small size of the liver be to some extent accounted for by the compensating function of the largely developed spleen 1 Although the above may afford sufficient explanation of the fact that the spleen is larger in the mammal than in the fish, it does not account for the difference of size in the various orders of each class. But may not the proportional size of the spleen in each order be also a question of development 1 for, on examination, it will be found that the propoi-tioual size of this organ frequently bears some relation to the development of the laterjil organs, as exhibited in the size and complex structure of the limbs, especially of the upper extremities If we take extreme cases, this will be more apparent; in the mam- malia, by way of illustration, the largest proportional size of the s]3lecn is to be found in the bats, and the smallest in the whales; whilst it is in the bats we meet with the highest development of the upper extremities, and in the whales the lowest. In the Felidce, with highly developed claws, as, for ex- ample, in the lion, the spleen is of much larger size than in other ordei-s of the camivora; whilst in the kangaroo the spleen is proportionately small, this reduced bulk co- existing with the diminished size of the upper extremities. The small size of the spleen in the marsupials and mouo- tremes is, however, capable of another explanation. In the Pachydermala, as a rule, the spleen is small. The seal, phoca vitulina, would, at first sight, appear to be an exception ; but as explained above, in amphibia and other animals of allied habits, the spleen, by its large size and dis- tensile structure, serves as a reservoir for the blood which
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