The Microscopic & General Anatomy of the Teeth: Human and ComparativeH. Milford, 1924 - 618 pages |
Expressions et termes fréquents
ameloblasts Anatomy animal appear arranged band blood-vessels Bolk border C. S. Tomes calcification calcospherites canine Carnivora cement cervical margin concave connective tissue connective-tissue connexion considered convex crown cusps deciduous dental lamina dentinal fibril dentinal tubes dentine deposit described distal surface distinct Ebner Elephant enamel organ enamel prisms epithelial cells epithelium eruption external epithelium fish follicle formation forming enamel functional glands groove heterodont human hypsodont incisors inner interglobular spaces interprismatic substance lacunæ layer lime salts longitudinal lower jaw Macropus mammalian mammals mandible mandibular marsupial enamel marsupials maxillary mesial and distal molar teeth Nasmyth's membrane nerve fibres odontoblasts osteoblasts outer papilla penetrate periodontal membrane permanent teeth Plate portion posterior premolar preparations prisms pulp cavity reptiles ridge Rodents root Röse Sargus seen separated sharks sheath shown side skull specimen stained stellate reticulum stratum intermedium striæ structure tion Tomes's processes tooth germ tooth-band transverse section tubular Ungulates upper jaw vascular
Fréquemment cités
Page vi - So it is in contemplation; if a man will begin with certainties, he shall end in doubts; but if he will be content to begin with doubts, he shall end in certainties.
Page 8 - On the contrary, in their earliest condition they are all similar, and the primordial germs of a man, a dog, a bird, a fish, a beetle, a snail, and a polype are, in no essential structural respects, distinguishable.
Page 7 - The calf, for instance, has inherited teeth, which never cut through the gums of the upper jaw, from an early progenitor having well-developed teeth...
Page 5 - ... how in the single instances the change of one species into another has actually taken place. The theory of descent remains unshaken even if our conception concerning the mode of descent should prove to be in need of revision. Such a revision seems now to be unavoidable.
Page 10 - The result, therefore, of this physical inquiry is, that we find no vestige of a beginning, — no prospect of an end"§.
Page 49 - The interprismatic substance appeared dark and the bridges are very conspicuous as white lines. FIG. 7. Elephant. From a section showing a wing process in the enamel. Compare with photograph, fig. 27. • FIG. 8. Elephant. From a section showing ridges and grooves, r. Ridges; g. grooves. Compare with photograph, fig. 27. FIG. 9. Two prisms from Elephant, showing needle-splitting (n) and inter-columnar bridges (6). FIG. 10. Fragment of Elephant enamel in transverse section. Two entire double concave...
Page 124 - Cell and tissue, shell and bone, leaf and flower, are so many portions of matter, and it is in obedience to the laws of physics that their particles have been moved, molded and conformed.
Page 132 - ... in the living body are the result of purely physical agencies, and to what degree they are affected by physiological and vital conditions, we are unable to determine, but it is seen that very firm membranes do arise in the absence of all organic substances, although, as Professor Philip says (19), 'a purely physical theory of the exchanges which take place across a living membrane is inadequate ; there is a physiological as well as a physical permeability '. The bearing of these observations...
Page 125 - The laws which regulate nltration, imbibition, and osmosis are fairly well known and can be experimentally verified. But we have undoubtedly some other force, or some other manifestation of force, in the case of living membranes. It probably is some physical or chemical property of living matter which has not yet been brought into line with the known chemical and physical forces which operate in the inorganic world. We cannot deny its existence, for it sometimes operates so as to neutralise the known...
Page 8 - ... germ cell, not from the parent body, and the germ cell owes its characteristics not to the body which bears it but to its descent from a preexisting germ cell of the same kind. Thus the body is as it were an offshoot from the germ cell. As far as inheritance Is concerned the body is merely the carrier of the germ cells which are held In trust for coming generations.