Medical and physical researches, or, Original memoirs in medicine, surgery, physiology, geology, zoology, and comparative anatomy / by R. Harlan.

  • Harlan, Richard, 1796-1843.
Date:
1835
Catalogue details

Licence: Public Domain Mark

Credit: Medical and physical researches, or, Original memoirs in medicine, surgery, physiology, geology, zoology, and comparative anatomy / by R. Harlan. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    pendicula vermiformis very large ; contents of the thorax displaying close analogy to the human; ventricles of Morgagni rather large, though not communicating with a sac in the throat, as in the Simia satyrus and some mon- keys ; sternum composed of only two pieces, like that hone in man, in which it differs from the Simise with tails. Twenty-five rings to the trachea, fourteen ribs on each side, fourteen dorsal vertebrae, seven cervical, five lum- bar, five sacral, and five coccygeal: but the most remark- able peculiarity remains to be noticed ; the subject proved to be a complete Hermaphrodite. Hermaphrodism, that is to say, individuals uniting in themselves the means of reproduction, without the con- currence of other individuals of their own species, appears to be, in some sort, a vegetable attribute; as among plants, the class Dioecia (Linn.) is the only one not hermaphro- dite. The nearer the animal approaches the vegetable kingdom, the more frequent and complete are the in- stances of hermaphrodism. This is of two distinct kinds: in the one, it is absolute, the animal possessing within it- self the powers of reproduction, as is instanced in the Bivalve shells, as the Oyster, in some of the Multivalves, as the Chiton, and in Zoophytes, Holothuria, &c.; whilst in Univalve shells, on the contrary, such as the Helix, Limnea, Planorbis, &c. although they unite the two sexes, yet the union of two individuals is necessary to fecunda- tion. The common garden snail, is a familiar example: animals of this description are properly termed Andro- gynous. The disposition, then, to hermaphrodism, is more rare as we advance in the scale of perfection, or rather to a more complex organization. Those cases said to have occurred in the higher orders of animals, may, with few exceptions, be attributed to mal-conformation of the genital organs, and to a mixture of the two sexes; which, according to the observations of Sir E. Home,* * Philosoph. Trans. 1799.