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according acid already animals appear arteries become birds blood blood-corpuscles body brain branches canal cavity cells chorion circulation closely colour completely connected consequence consists constitution contained continues contractions corpuscles course covered decidua delicate described diameter distinct divided effect elements embryo entire experiments external extremely fact fibres figures fluid formation germinal glands globules granular granules greater heart human immediately instance intestine kind laminŠ larger layer length less mammalia mass matter means membrane minute motions muscles muscular nature nerves nervous nuclei observed occur organs ovary ovum particular pass period Physiology placenta portion present produced quantity reference regard round secretion seen separated side simple smaller spermatozoa stomach structure substance surface surrounded third tion tissue tube uterus various vascular veins vesicle vessels Vide whole yolk
Page 226 - ... yet in their primary state, from the indifferent cells, out of which entire organs are evolved. When first a nerve can be distinguished as such, it presents itself as a pale cord with a longitudinal fibrillation and in this cord a multitude of nuclei are apparent.
Page 153 - Smallest set here mentioned, makes its appearance on the whole of the inner surface of the membrane which now invests the yelk. The mulberry-like structure then passes from the centre of the yelk to a certain part of that layer (the vesicles of the latter coalescing with those of the former, where the two sets are in contact, to form a membrane — the future...
Page 416 - Malpighian tufts. After it has pierced the capsule, the twig dilates, and suddenly divides and subdivides itself into several minute branches, terminating in convoluted capillaries, which are collected in the form of a ball; and from the interior of the ball the solitary efferent vessel emerges, passing out of the capsule by the side of the single afferent vessel. This ball lies loose and bare in the capsule, being attached to it only by its afferent and efferent vessel, and is divided into as many...
Page 222 - All the organic tissues,' says Dr. Schwann, ' however different they may be, have one common principle of development as their basis, viz. the formation of cells ; that is to say, nature never unites molecules immediately into a fibre, a tube, and so forth, but she always in the first instance forms a round cell, or changes, when it is requisite, the cells into the various primary tissues as they present themselves in the adult state.
Page 447 - ... [This was the case till the present year (1842), which has witnessed a revival of Doellinger's notions by Dr. Martin Barry, who appears inclined...
Page 226 - On the occurrence of this secondary deposit, the nuclei of the cells are generally absorbed ; yet a few may still be found to remain for some time longer, when they are observed lying outwardly between the deposited substance and the cell-membrane (fig.
Page 67 - ... regards the inferior animals there is diversity of opinion amongst the observers as to whether the spermatozoa reach the ovary ; whilst Prevost and Dumas found them in the fallopian tubes, and Bischoff in the ovary itself, Dr. Barry found in the rabbit that in 17 out of 19 instances he was unable to discover spermatozoa in the fluid collected from the surface of the ovary, on one occasion he found a single spermatozoon, which was dead, while the ova had escaped. On a second occasion he found...
Page 153 - ... filled with a colourless and pellucid fluid. This hollow spherical body seems to be the true germ. The vesicle containing it disappears, and in its place is seen an elliptical depression filled -with a pellucid fluid. In the centre of this depression is the germ, still presenting the appearance of a hollow sphere.
Page 233 - The human blood corpuscles or red globules," says Dr. Morton, " are flattened circular discs, with a central concavity or depression on each surface, which, in some respects, gives them an annular appearance. They vary between the 300th and the 400th of a line in diameter, and their thickness is about one fourth of that measure. Each corpuscle is a cell, of which the envelope is elastic, homogeneous, pellucid, and colorless; and the contents are of a more or less deeply red color. They are, however,...
Page 489 - Now as, in some cases, sensation exists without volition and as almost all nerves arise by distinct filaments, I am of opinion, that wherever a part having both sensation and motion, is supplied from one nervous trunk, that trunk envelopes both a nerve of sensation and one of volition.