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"Longitudinal section through fertilized ovule of a spruce. p, pollen grains; t, pollen tubes; n neck of the archegonium; a, body of archegonium with nucleus; e, embryo sac filled with endosperm." -Bergen, 1896

Spruce Ovule

"Longitudinal section through fertilized ovule of a spruce. p, pollen grains; t, pollen tubes; n neck…

Men carrying someone in a palanquin in China.

Palanquin

Men carrying someone in a palanquin in China.

"The Lungs. 1, Summit of lungs. 2, Base of lungs. 3, Trachea. 4, Right bronchus. 5, Left bronchus. 6, Left aurical of heart. 7, Left superior pulmonary vein. 8, Right superior pulmonary vein. 9, Left ventricle of heart. 10, Right ventricle of heart." -Foster, 1921

Lungs

"The Lungs. 1, Summit of lungs. 2, Base of lungs. 3, Trachea. 4, Right bronchus. 5, Left bronchus. 6,…

"Superficial arteries and nerves of the face and neck. 1, Temporal artery; 2, artery behind the ear; 3, occipital artery; 4, greater occipital nerve; 5, smaller occipital nerve; 6, nerve of the neck; 7, trapezius muscle; 8, clavicular nerves; 9, clavicle; 10, sterno-cleido-mastoid muscle; 11, outer artery of the head; 12, inner artery of the head; 13, salivary gland; 14, nerves of the lower jaw; 15, outer maxillary artery; 16, nerve of the chin; 17, circular muscle of the mouth; 18, greater yoke muscle; 19, nerves below the eye; 20, masseter, or chewing muscle; 21, ear passage; 22, arteries of the forehead; 23; nerves of the forehead; 24, eye-closing muscle; 25, facial artery; 26, facial nerve." -Foster, 1921

Arteries and Nerves

"Superficial arteries and nerves of the face and neck. 1, Temporal artery; 2, artery behind the ear;…

"Nerves of the had. 1, Nerves of the skin; 2, tendons; 3, arteries of the palm of the hand; 4, elbow nerve; 5, elbow artery; 6, nerve of the forearm; 7, nerve of the under-arm; 8, artery of the under-arm." -Foster, 1921

Hand Nerves

"Nerves of the had. 1, Nerves of the skin; 2, tendons; 3, arteries of the palm of the hand; 4, elbow…

"Thorax and abdomen. 1, 1, 1, 1. Muscles of the chest. 2, 2, 2, 2. Ribs. 3, 3, 3. Upper, middle and lower lobes of the right lung. 4, 4. Lobes of the left lung. 5, Right ventricle of the heart. 6. Left ventricle. 7. Right auricle. 8. Left auricle. 9. Pulmonary artery. 10. Aorta. 11. Descending vena cava. 12. Trachea. 13. Oesophagus. 14, 14, 14, 14. Pleura. 15, 15. Diaphragm. 16, 16. Right and left lobes of the liver. 17. Gall cyst. 18. Stomach. 19. Duodenum. 20. Ascending colon. 21. Transverse colon. 22. Descending colon. 23, 23. Small intestine. 24. Thoracic duct opening into the left subclavian vein. 25. Spleen." -Foster, 1921

Thorax and Abdomen

"Thorax and abdomen. 1, 1, 1, 1. Muscles of the chest. 2, 2, 2, 2. Ribs. 3, 3, 3. Upper, middle and…

(1799-1850) French novelist and playwright most famous for Eugenie Grandet and La Comedie Humaine.

Honore de Balzac

(1799-1850) French novelist and playwright most famous for Eugenie Grandet and La Comedie Humaine.

A bony structure located at the bottom of the spine. The human sacrum forms the back part of the pelvis, is roughly triangular in shape, consists of five united vertebrae, and from its solidity it is well adapted to serve as the keystone of the pelvic arch.

Pelvic Bone, Male

A bony structure located at the bottom of the spine. The human sacrum forms the back part of the pelvis,…

Human red blood corpuscles. Highly magnified.

Blood Corpuscles

Human red blood corpuscles. Highly magnified.

The chief organs of the body from the side. Labels: a, arch of the aorta or main artery of the trunk; c, large intestine; d, diaphragm; e, throat; g, lung; k, kidney; l, spinal cord within the back bone; m, main artery divided to go to h legs; n, pancreas; o, gullet; s, spleen; tr, wind pipe; t, main vein of body; ap, appendix.

View of Organs from the Side

The chief organs of the body from the side. Labels: a, arch of the aorta or main artery of the trunk;…

The human skeleton.

The Human Skeleton

The human skeleton.

A human skeleton from the back.

Back View of a Human Skeleton

A human skeleton from the back.

A diagram of the human muscular system.

A Diagram of the Human Muscular System

A diagram of the human muscular system.

The molar teeth of a human, horse and dog. The first image to the left in a molar tooth of a horse. Labels: 1, The enamel. 2, The ivory. 3, Canals for blood vessels. The center image is a molar tooth of a human. Label: 1, The enamel. 2, The ivory. 3, The cavity containing blood vessels. 4, 5, Artery and nerve. The image on the right is a molar tooth of a dog. Labels: 1, The enamel. 2, The ivory. 3, Cavity for blood-vessels.

Comparison of the Molar Teeth of a Human, Horse, and Dog

The molar teeth of a human, horse and dog. The first image to the left in a molar tooth of a horse.…

The human circulatory organs.

The Circulatory Organs

The human circulatory organs.

Diagram of human brain in vertical section, showing the situation of the different ganglia and the course of fibers. Labels: 1, Olfactory ganglion. 2, Hemisphere. 3, Corpus striatum. 4, Optic thalamus. 5, Tubercula quadrigemina. 6, Cerebellum. 7, Ganglion of tuber annulare. 8, Ganglion of medulla oblongata.

Diagram of Human Brain in Vertical Section

Diagram of human brain in vertical section, showing the situation of the different ganglia and the course…

"Cross-sections of leaves of an oak (Quercus novimexicana), showing the effect of different light conditions on the internal anatomy. 1, from leaf growing in sunlight; 2, from leaf growing in the shade." -Gager, 1916

Oak Leaf Cross-Section

"Cross-sections of leaves of an oak (Quercus novimexicana), showing the effect of different light conditions…

"Diagram showing tissue-systems in young stem of castor-oil plant (Ricinus communis), as seen in cross-section. ep, epidermis; cor, cortex; p, pith or medulla; b, fibro-vascular bundle; ph, phloem; ca, cambium; x, xylem; ic, interfascicular cambium." -Gager, 1916

Castor-Oil Plant Stem

"Diagram showing tissue-systems in young stem of castor-oil plant (Ricinus communis), as seen in cross-section.…

"The castor-oil plant (Ricinus communis). Portion of cross-section of young stem. co, Cortex; p, pith or medulla; e, epidermis; ph, phloem; ca, cambium; x, xylem. The last three elements compose the fibro-vascular bundle, the cambium being continuous from bundle to bundle; the portion between the bundles is called interfascicular cambium." -Gager, 1916

Castor-Oil Plant Stem

"The castor-oil plant (Ricinus communis). Portion of cross-section of young stem. co, Cortex; p, pith…

The human skull. Labels: 1, frontal lobe; 2, parietal lobe; 3, temporal lobe; 4, the sphenoid bone; 5, ethmoid bone; 6, superior maxillary (upper jaw) bone; 7, malar bone; 8, lachrymal bone; 9, nasal bone; 10, inferior maxillary (lower jaw) bone.

The Skull

The human skull. Labels: 1, frontal lobe; 2, parietal lobe; 3, temporal lobe; 4, the sphenoid bone;…

The human torso. Labels: A, the heart; B, the lungs drawn aside to show the internal organs; C, the diaphragm; D, the liver; E, the gall cyst; F, the stomach; G, the small intestines; H, the transverse colon.

Torso

The human torso. Labels: A, the heart; B, the lungs drawn aside to show the internal organs; C, the…

A magnified view of corpuscles of human blood compared to animal blood. Labels: A, corpuscles of human blood; B, corpuscles in the blood of an animal (a non-mammal).

Corpuscles of Human and Animal Blood

A magnified view of corpuscles of human blood compared to animal blood. Labels: A, corpuscles of human…

The human nervous system includes the brain, spinal cord, and the nerves. Labels: A, cerebrum; B, cerebellum.

Nervous System

The human nervous system includes the brain, spinal cord, and the nerves. Labels: A, cerebrum; B, cerebellum.

The human ear. Labels: A, vestibule or antechamber; B, auditory canal; C, the hammer, anvil, and the stirrup; D, semicircular canals; E, cochlea; G, Eustachian tube.

Ear

The human ear. Labels: A, vestibule or antechamber; B, auditory canal; C, the hammer, anvil, and the…

The human eye. Labels: a, crystalline lens; b, retina; c, cornea; d, sclerotic; e, choroid; g, ciliary processes; h, vitreous humor; k, pupil; i, iris; o, optic nerve.

Eye

The human eye. Labels: a, crystalline lens; b, retina; c, cornea; d, sclerotic; e, choroid; g, ciliary…

The power possessed by the hand of a human is chiefly depended upon the size and power of the thumb, which is more developed in humans than it is in the highest apes. The thumb of the human hand can be brought into exact opposition to the extremities of all the fingers, whether singly or in combination; while in those quandrumana which most nearly approach man, the thumb is so short, and the fingers are so weak that they can never be opposed to each other with any degree of force. The human foot is, in proportion to the side of the whole body, larger, broader, and stronger than that of any other mammal.

Comparison of the Hand and the Foot of a Monkey and Human

The power possessed by the hand of a human is chiefly depended upon the size and power of the thumb,…

A diagram of the human skeleton.

The Human Skeleton

A diagram of the human skeleton.

The diagram of a human ovum, showing the parts of an animal cell.

A Diagram of the Human Ovum

The diagram of a human ovum, showing the parts of an animal cell.

The diagram of a human ovum undergoing segmentation. Labels: a, human ovum; b, ovum divided into two; c, ovum divided into four; d, process has ended in the production of the so-called mulberry mass.

The Human Ovum Undergoing Segmentation

The diagram of a human ovum undergoing segmentation. Labels: a, human ovum; b, ovum divided into two;…

Ciliated epithelium from the human trachea. Large fully formed cell. Labels: b, shorter cell; c, developing cells with more than one nucleus.

Ciliated Epithelium

Ciliated epithelium from the human trachea. Large fully formed cell. Labels: b, shorter cell; c, developing…

The bone contains a multitude of small irregular spaces, approximately fusiform in shape, called lacunae, with very minute canals leading from them and anastomosing with similar little prolongations from the other lacunae. Shown is a longitudinal section from the human ulna, showing Haversian canal, lacunae, and canaliculi.

Microscopic Structure of Bone

The bone contains a multitude of small irregular spaces, approximately fusiform in shape, called lacunae,…

Bone corpuscles with their processes as seen in a thin section of human bone.

Bone Corpuscles

Bone corpuscles with their processes as seen in a thin section of human bone.

Lamellae torn off from a decalcified human parietal bone at some depth from the surface. Labels: a, lamellae, showing reticular fibers; b, darker part, where several lamellae are superposed; perforating fibers. Apertures through which perforating fibers has passed, are seen especially in the lower part of the figure.

Lamellae

Lamellae torn off from a decalcified human parietal bone at some depth from the surface. Labels: a,…

Osteoblasts from the parietal bone of a human embryo, thirteen weeks old. Labels: a, bony septa with cells of the lacunae; b, layers of osteoblasts; c, the latter in transition to bone corpuscles.

Osteoblasts

Osteoblasts from the parietal bone of a human embryo, thirteen weeks old. Labels: a, bony septa with…

Transverse section of femur of a human embryo about eleven weeks old. Labels: a, rudimentary Haversian canal in cross sections; b, in longitudinal section; c, osteoblast; d, newly formed osseous substance of a lighter color; e, that of greater age; f, lacunae with their cells; g, a cell still united to an osteoblast.

Formation of Compact Bone in a Human

Transverse section of femur of a human embryo about eleven weeks old. Labels: a, rudimentary Haversian…

Longitudinal section (A) and transverse section (B) of a human molar tooth. Labels: c, cement; d, dentine; e, enamel; v, pulp cavity

Structure of a Molar

Longitudinal section (A) and transverse section (B) of a human molar tooth. Labels: c, cement; d, dentine;…

Transverse section through muscular fibers of human tongue. The muscle corpuscles are indicated by their deeply stained nuclei situated at the inside of the sarcolemma. Each muscle fiber shows "Cohnheim's fields," that is, the sarcous elements in transverse section separated by clear (apparently linear) interstitial substance.

Muscular Fibers of the Human Tongue

Transverse section through muscular fibers of human tongue. The muscle corpuscles are indicated by their…

A. Portion of a medium sized human muscular fiber. B. Separated bundles of fibrils equally magnified. Labels: a, larger, and b, smaller collections; c, still smaller; d, smallest which could be detached, possibly representing a single series of sarcous element.

Muscular Fiber

A. Portion of a medium sized human muscular fiber. B. Separated bundles of fibrils equally magnified.…

Different forms of ganglion cells. A, a, round ball-shaped unipolar cell from the human Gasserian ganglion. Two cells only show the process f; b, spindle shaped; c, multipolar ganglion cell from he spinal cord of the ox. d, D, Purkinjee ganglion cells from human cerebellum; ax, axis cylinder process; p, protoplasmic process; h, h, two cells surrounded with a nucleated sheath.

Different Forms of Ganglion Cells

Different forms of ganglion cells. A, a, round ball-shaped unipolar cell from the human Gasserian ganglion.…

An isolated ganglion cell of a human, showing sheath with nucleated cell lining, B. A Ganglion cell, with nucleus and nucleolus. C, Branched process. D. Unbranched process.

Ganglion Cell, Structure of

An isolated ganglion cell of a human, showing sheath with nucleated cell lining, B. A Ganglion cell,…

The Pacinian bodies or corpuscles are elongated oval bodies situated on some of the cerebrospinal and sympathetic nerves, especially the cutaneous nerves of the hands and feet; and on branches of the large sympathetic plexus about the abdominal aorta. Shown are the extremities of a nerve of the finger with Pacinian corpuscles attached.

Pacinian Corpuscles in a Human

The Pacinian bodies or corpuscles are elongated oval bodies situated on some of the cerebrospinal and…

The Pacinian bodies or corpuscles are elongated oval bodies situated on some of the cerebrospinal and sympathetic nerves, especially the cutaneous nerves of the hands and feet; and on branches of the large sympathetic plexus about the abdominal aorta. Shown is the summit of a Pacinian corpuscle of a human finger, showing the endothelial membranes linking the capsules.

Pacinian Corpuscle of a Human

The Pacinian bodies or corpuscles are elongated oval bodies situated on some of the cerebrospinal and…

Touch corpuscles are found in the papillae of the skin of the fingers and toes, or among its epithelium; they may be simple or compound; when simple, they are large and slightly flattened transparent nucleated ganglion cells, enclosed in a capsule; when compound the capsule contains several smalls cells. Show is a touch corpuscle of Meissner, from the skin of the human hand.

Touch Corpuscle of Meissner

Touch corpuscles are found in the papillae of the skin of the fingers and toes, or among its epithelium;…

The clotting of the blood is due to the development in it of a substance called fibrin which appears as a meshwork of fine fibrils. Reticulum of fibrin, from a drop of human blood, after treatment rosanilin.

Reticulum of Fibrin

The clotting of the blood is due to the development in it of a substance called fibrin which appears…

Acetic acid (dilute) causes the nucleus of the red blood cells in the frog to become more clearly defined; if the action is prolonged, the nucleus becomes strongly granulated, and all the coloring matter seems to be concentrated in it, the surrounding cell substance and outline of the cell becoming almost invisible; after a time the cells lose their color altogether. The cells shown represent the successive stages of change. A similar loss of color occurs in the red cells of human blood, which , however, from the absence of nuclei, seem to disappear entirely.

Effect of Acetic Acid on Red Blood Cells

Acetic acid (dilute) causes the nucleus of the red blood cells in the frog to become more clearly defined;…

When a 2 percent fresh solution of tannic acid is applied to frog's blood it causes the appearance of a sharply defined little knob, projecting from the free surface (Robert's macula): the coloring matter becomes at the same concentrated in the nucleus, which grows more distinct. A somewhat similar effect is produced on the human blood corpuscle.

Effect of Tannin on Red Blood Cells

When a 2 percent fresh solution of tannic acid is applied to frog's blood it causes the appearance of…

Human colorless blood corpuscle, showing its successive changes of outline within ten minutes when kept moist on a warm stage.

The Change of Colorless Blood Corpuscles

Human colorless blood corpuscle, showing its successive changes of outline within ten minutes when kept…

Ciliary epithelium of the human trachea. Labels: a, layer of longitudinally arranged elastic fibers; b, basement membrane; c, deepest cells, circular in form; d, intermediate elongated cells; e, outermost layer of cells fully developed and bearing cilia.

Ciliary Epithelium

Ciliary epithelium of the human trachea. Labels: a, layer of longitudinally arranged elastic fibers;…

The capillary network of the pulmonary blood vessels in the human lung.

Capillary Network in Lung

The capillary network of the pulmonary blood vessels in the human lung.

A tonsil consists of an elevation of the mucous membrane presenting 12 to 15 orifices which lead into crypts or recesses, in the walls of which are placed nodules of adenoid or lymphoid tissue. Shown is a vertical section through a crypt of the human tonsil. Labels: 1, entrance to the crypt; 2 and 3, the framework or adenoid tissue; 4, the enclosing fibrous tissue; a and b, lymphatic follicles; 5 and 6, blood vessels.

Crypt of Tonsil

A tonsil consists of an elevation of the mucous membrane presenting 12 to 15 orifices which lead into…

A, Villus of sheep. B, Villi of human.

Villus of Humans and Sheep

A, Villus of sheep. B, Villi of human.

Sebaceous gland from the human skin.

Sebaceous Gland from Human Skin

Sebaceous gland from the human skin.

Section through the gray matter of the human cerebellum.

Gray Matter of Cerebellum

Section through the gray matter of the human cerebellum.

Brain of the Orangoutang, showing arrangement of the convolutions. Sy, fissure of Sylvius; R, fissure of Rolando; E P, external perpendicular fissure; Olf, olfactory lobe; Cb, cerebellum; PV, pons Varolii; MO, medulla oblongata. As contrasted with the human brain, the frontal lobe is short and small relatively, the fissure of Sylvius is oblique, the temporo-sphenoidal lobe very prominent, and the external perpendicular fissure very well marked.

Brain of the Orangutan

Brain of the Orangoutang, showing arrangement of the convolutions. Sy, fissure of Sylvius; R, fissure…

Section through the choroid coat of the human eye. Labels: 1, elastic membrane, structureless or finely fibrillated; 2, chorio-capillaris or tunica Ruyschiana; 3, Proper substance of the choroid with large vessels cut through; 4, suprachoroidea; 5, sclerotic.

Section Through the Choroid Coat

Section through the choroid coat of the human eye. Labels: 1, elastic membrane, structureless or finely…

Section through the macula lutea and fovea centralis of the human retina. Labels: a, fovea; b, descent of the macula towards fovea. The numbers indicate the layers of the retina: 1, membrana limitans interna; 2, optic nerve fibers; 3, layer of ganglionic corpuscles; 4, inner molecular layer; 5, inner nuclear layer; 6, intergranular, internuclear, or outer molecular layer. 7, external nuclear layer; 8, membrana limitans externa; 9, layer of rods and cones; 10, pigment-cell layer.

Layers of the Retina

Section through the macula lutea and fovea centralis of the human retina. Labels: a, fovea; b, descent…

Spermatozoa of the salamander (1) and human (2). Labels: a, long pointed head; b, elliptical structure ; c, filiform body; d, fine filament; e, homogeneous membrane.

Spermatozoa of a Salamander and Human

Spermatozoa of the salamander (1) and human (2). Labels: a, long pointed head; b, elliptical structure…

Diagrammatic section showing the relation in a mammal between the primitive alimentary canal and the membranes of the ovum. The stage represented in this diagram corresponds to that of the fifteenth or seventeenth day in the human embryo, previous to the expansion of the allantois; c, the villous chorion; a, the amnion; a', the place of convergence of the amnion and reflexion of the false amnion a", or outer or corneous layer; e, the head and trunk of the embryo, comprising the primitive vertebrae and cerebrospinal axis; i, the simple alimentary canal in its upper and lower portions. Immediately beneath the right hand i is seen the fetal heart, lying in the anterior part of the pleuroperitoneal cavity; v, the yolk sac or umbilical vesicle; vi, the vitellointestinal opening; u, the allantois connected by a pedicle with the anal portion of the alimentary canal.

Membranes of the Ovum

Diagrammatic section showing the relation in a mammal between the primitive alimentary canal and the…

Human embryo of fifth week with umbilical vesicle. The human umbilical vesicle never exceeds the size of a small pea.

Embryo of Fifth Week

Human embryo of fifth week with umbilical vesicle. The human umbilical vesicle never exceeds the size…

Very soon after the entrance of the ovum into the uterus, in the human subject, the outer surface of the chorion is found beset with fine processes, the so-called chorion villi, which give it a rough and shaggy appearance. a, chorion with villi. The villi are shown to be best developed in the part of the chorion to which the allantois is extending, this portion ultimately becomes the placenta. ; b, space between the two layers of the amnion; c, amniotic cavity; d, situation of the intestine, showing its connection with the umbilical vesicle; e, umbilical vesicle; f, situation of heart and vessels; g, allantois.

Chorion Villi

Very soon after the entrance of the ovum into the uterus, in the human subject, the outer surface of…