Lectures on Comparative Anatomy

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The Lancet, 1834
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Seite 1005 - The life of animals exhibits a continued series of changes, which occupy so short a period that we can generally trace their entire order of succession, and perceive the whole chain of their metamorphoses. But the metamorphoses of species proceed so slowly with regard to us, that we can neither perceive their origin, their maturity, nor their decay ; and we ascribe to them a kind of perpetuity on the earth.
Seite 914 - We find it a common principle in the animal machine, that every part increases in some degree according to the action required. Thus we find muscles increase in size when much exercised ; vessels become larger in proportion to the necessity of supply, as for instance in the gravid uterus ; the external carotids in the stag, also, when his horns are growing, are much larger than at any other time...
Seite 160 - ... before the pressure on the secreting vessels of the kidney would be so great as to put a stop to their office, or to dilate the ureters. Nature can accommodate herself for several days, and in some instances for weeks, to a complete suppression of the secretion of urine ; and for a very long time to a partial secretion of it.
Seite 914 - ... his predecessors in unfolding the structure of the digestive organs of animalcules. Such coloured organic matter, diffused as fine particles mechanically suspended in the water in which animalcules are placed, is readily swallowed by them, and renders visible, through their transparent bodies, the form and disposition of their alimentary cavities ; but, however long they remain in these coloured infusions with their stomachs...
Seite 914 - ... to break down and remove the hard coverings of grains. In the climbing frugivorous cockatoos, parrots, and maccaws, the broad and powerful bills serve as prehensile organs, and to break the hard shelly coverings of seeds. The bills of eagles and vultures, hawks and owls, and other rapacious birds, are strong, short, compressed, arched, curved at the point, dense in their texture, and with sharp cutting edges, to seize, and tear, and cut the flesh of living prey. So that the forms of these external...
Seite 914 - I have observed, that in inflammation the vessels become larger, more blood passes, and there appear to be more actions taking place ; but the nerves do not seem to undergo any change. The nerves of the gravid uterus are the same as when it is in the natural state ; neither do the branches of the fifth and seventh pair of nerves in the stag become larger.
Seite 914 - ... however long they remain in these coloured infusions, with their stomachs distended with the colouring matter, it is not perceived to communicate the slightest tinge to the general cellular tissue of their body.
Seite 917 - This principle is thus alluded to by Dr. Grant:—" It is the restless activity of the worm and of the insect that makes every fibre of their body, as it were, a heart to propel their blood and circulate their fluids, while the slowcreeping snail that feeds upon the turf has a heart as complicated as that of the red-blooded, vertebrated fish, that bounds with such velocity through the deep. It is because the fish is muscular and active in every point that it requires no more heart than a snail to...
Seite 914 - Müller supposed that they fed upon water, from their stomachs being most frequently filled with that fluid. Ehrenberg has more extensively employed opaque colouring matter to detect the forms of these internal cavities, and by using principally carmine, sap-green, and indigo, carefully freed from all impurities which might prevent their being swallowed, he has succeeded better than his predecessors in unfolding the structure of the digestive organs of animalcules. Such coloured organic matter, diffused...
Seite 154 - Grant asserts that nearly five hundred millions are contained in a single drop of water, that is, as many as there are individuals of our own race on the earth...

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