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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    Rhodes, Young and Bird, Noggerath, Agardh, Nilson, Mantelle, Artis, Lyelle, Granger, Nau, Martius, are among those who have most conduced to elucidate this branch of science. To Stern- berg, Brongniart, and Lindley and Hutton, we are indebted for a systematic classification of them; together with the discovery of numerous species. in regard to those laws of co-existence, in conformity with which the animal frame is constructed, they are found to exist only to a limited extent in the anatomy of the vegetable kingdom. The organs of plants are divided into two great classes;—those of vegetation, and those of fructification. Nutrient vessels forming the basis for determining the rela- tions of position, and often even the form of organs, are evidently more important than the parenchyma, or cellular matter, which surrounds and unites them : the mode of distribution of these ves- sels may develope the true affinities of vegetables; consequently, their disposition is the principal thing to be observed in every or- gan. When we are able to detect the interior structure of the stalk, this disposition demands close inspection : but when we can- not examine this, the mode of growth of the stalk being constant- ly associated with this interior structure, and the external form of the stalk depending on its mode of growth, the form of the stalk is sufficient to determine, with considerable accuracy, its internal structure. The next most important character of the stalk, is the mode in which the leaf is inserted at its base; a character depending ne- cessarily on the structure of the stalk, and not of the leaf, as it is the former which produces and developes the latter: the same may be observed of the vessels which run from the stalk to the petiole.—(Sternberg.) Such are the modifications of structure which require our par- ticular attention in the present investigation, as they enable us to determine the analogies which unite the fossil with recent vege- tables. In the leaf the disposition of the nervures will enable us to de- termine the families to which they belong. In these researches, the characters of the flowers, are comparatively unimportant; this part being seldom or never met with in a fossil state. The fruit presents us with a variety of structure; and the ad- herence, or non-adherence of the calix; the number of compart-