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acid algae alimentary canal animal kingdom appearance artery become blastoderm body branches cells central colour commencing connective tissue cord corpuscles described Dog-fish duct ectoderm embryo endoderm endothelium epiblast epithelium exhibited fibres filaments fluid formation ganglia ganglion Gastraea-theory gastrula genus germ germ-lamellae germination gonidia granular granules groove groups growth Hydra hyphae hypoblast inch intestinal involution lamella lateral layer lichens longitudinal lymphatic mass medullary membrane mesoblast Metazoa microscope mode Mollusca Mucor muscles muscular mycelium Navicula nerve-trunks nerves notochord nuclei observations occur ontogenesis organs origin outer Oviduct parasitic plant plate pleuro-peritoneal cavity polypide Polyzoa portion present primitive prothallus protoplasm Protozoa Rhabdopleura sections seen segmentation separated shell shell-gland showed side slide species specimens sporangia sporangium spores stage stained stem structure substance surface tentacular tion transverse tube valve vertebral Vertebrata vessels wall Wolffian Wolffian duct yolk zygospore
Página 275 - ... the dentine more transparent, and softer, so as to be cut with a knife. The acids which may actually effect the first changes in the production of caries are such as are taken with food, or in medicines, or such as are formed in the mouth itself by some abnormality in our secretions, which should be alkaline, or by an acid fermentation of particles of food. But acids alone will not account for all the phenomena ol caries in the teeth.
Página 150 - A complete identity of structure connects the " foundation membranes" of the Medusae with the corresponding organs in the rest of the series ; and it is curious to remark, that throughout, the outer and inner membranes appear to bear the same physiological relation to one another as do the serous and mucous layers of the germ ; the outer becoming developed into the muscular system and giving rise to the organs of offence and defence ; the inner, on the other hand, appearing to be more closely subservient...
Página 112 - ... and that the connection between the hypha and gonidia is of such a nature as to exclude all possibility of the one organ being produced by the other. This he thinks is the only way in which it can be accounted for that the gonidia of diverse lichens should be almost identical. Dr. Nylander...
Página 170 - December 13th, on the cryptogamic vegetation which he had found within the egg of an ostrich. This egg had been given him at Cairo, and was still fresh, the air space having not even been formed. He soon, however, noticed the appearance of dark blotches within the shell, and having broken it open to ascertain the cause, he found that they were produced by the growth of minute fungi. Instances of a similar kind had already been studied by him, and he had communicated the results to the Botanical Congress...
Página 162 - No connection can be traced between the numbers of bacteria, spores, &c., present in the air and the occurrence of diarrhoea, dysentery, cholera, ague or dengue ; nor between the presence or abundance of any special form or forms of cells, and the prevalence of any of these diseases.
Página 85 - Genersich f have shown that the fasciae, in virtue of this structure, play a very important part in keeping up the flow of lymph through the lymphatic vessels. His first experiment was as follows : A piece of fascia was removed from the leg of a dog, and tied over the mouth of a small glass funnel with the inner side (ie the side next to the muscles) uppermost.
Página 355 - Echinoderms, and the latter is seen in its full development in the adult Rotifera, and in the larval Gasteropoda and Pteropoda. The identity of the velum of larval Gasteropods, with the ciliated disks of Rotifera, seems to admit of little doubt, and it would be well to have one term, eg, velum, by which to describe both. The Trochosphere is the earlier, more or less spherical form in which the velum is represented by an annular ciliated ridge, and which is sometimes (eg, Chiton) provided with a polar...
Página 275 - ... internal or vital, as external and chemical. Decay begins at the surface, and there it must be checked, if checked at all. It is chiefly caused by acids, and by a certain fungus, the leptothrix buccalis, found abundantly in the mouth. Under the microscope, the fungus appears as a gray, finely-granular mass or matrix, with filaments delicate and stiff, which erect themselves above the surface of this granular s'ubstance, so as to resemble an uneven turf.
Página 275 - Bowditch, in examining forty persons of different professions, and living different kinds of life, found in almost all vegetable and animal parasites. The parasites were numerous in proportion to the neglect of cleanliness. The means ordinarily employed to clean the teeth had no effect on the parasites, while soapy water appeared to destroy them.
Página 74 - Was würden wir von dem Architekten sagen, der durch eine Seitentüre in einen Palast gekommen wäre und nun, bei Beschreibung und Darstellung eines solchen Gebäudes, alles auf diese erste untergeordnete Seite beziehen wollte? und doch geschieht dies in den Wissenschaften jeden Tag.