"The European hedge woundwort, a tall hairy plant, with heart-shaped leaves, and numerous whorls of…
Nerve fibers. Labels: a, nerve-fiber, showing complete interruption of the white substance; b, another…
Diagram showing anatomy of the spinal nerve roots and adjacent parts. Labels: G., gray matter of the…
Red and white corpuscles (cells) of the blood, magnified. Labels: A, moderately magnified, the red corpuscles…
Plan of the blood vessels connected with the tubules. "The blood passes downwards in straight vessels…
"Experiment to illustrate electrostatic induction. The leaves will diverge, ever though the charged…
"Faraday's ice pail experiment. An ice pail P connected with gold leaves of an electroscope C, is placed…
Subcutaneous areolar tissue from a young rabbit, highly magnified. The white fibers are in wavy bundles,…
"In order that the successive wheels should revolve in the same time, and their circumfrences should…
"Although a ray of light will pass in a straight line, when not interrupted, yet when it passes obliquely…
"If light from a highly luminous body is admitted to a darkened room through a small hole in the shutter…
"The prism will deflect the red and orange, and form a reddish colored image at n. The violet, indigo,…
"A prism is used to disperse ordinary light, and slits are cut in paper S to only allow yellow and blue…
"A long ribbon of white paper is attached on a spool, and connected to a receiver that is wired to a…
Villi of the small intestine, magnified about 80 diameters. In the left-hand figure the lacteals, a,b,c,…
Vertical section of the intestinal mucous membrane of the rabbit. Two villi are represented, in one…
Blood corpuscles. Labels: A, magnified about 400 diameters. The red corpuscles have arranged themselves…
White blood corpuscle (cell), sketched at successive intervals of a few seconds to illustrate the changes…
Circulation in frog's foot under a microscope. Labels: A, walls of capillaries; B, tissue of web lying…
"Features six movable pulleys aligned on the same axis. This pulley was invented to reduce the friction…
"Since air is a rarer medium and water is denser, as ray A passes into the water, it is refracted to…
The right retina as it would be seen if the front part of the eyeball with the lens and vitreous humor…
White fibrous tissue, a type of connective tissue composed of smaller fine wavy interlacing fibers which…
Yellow fibrous tissue, a type of connective tissue composed of larger fibers which branch and join each…
A diagram of nerve tubules A nerve tube consists of a white portion which is fatty, and which protects…
Bag with four white, four striped, and two black marbles used for a probability activity.
Bag with four white, three black, and three striped marbles used for a probability activity.
Bag with four striped, three black, and three white marbles used for a probability activity.
Bag with four black, four white, and two striped marbles used for a probability activity.
Bag with four black, three white, and three striped marbles used for a probability activity.
Bag with four black, four striped, and two white marbles used for a probability activity.
"The general appearance of the aurora is that of an arch of white light rising from the horizon, like…
Cross-section of the brain. Here the upper half of the brain is cut off, and you see the upper cut surface…
Half Cent (1/2 cent) United States coin from 1793. Obverse has a left-facing profile of Liberty with…
Cent (1 cent) United States coin from 1793. Obverse has a right-facing Liberty with LIBERTY above and…
Blood corpuscles (cells). Labels: A, magnified about 400 diameters. The red corpuscles have arranged…
A white blood corpuscle sketched at successive intervals of a few seconds to illustrate the change of…
Villi of the small intestine; magnified about 80 diameters. In the right hand figure the lacteals, a,…
Leaves - simple, alternate, edge entire. Outline - long oval. Apex - pointed. Base - pointed. Leaf -…
Leaves - Simple, alternate, edge entire. Outline - long oval or slightly reverse egg-shape. Apex, slightly…
Leaves - Simple, alternate, edge entire. Outline - long oval or slightly reverse egg-shape. Apex, short,…
Leaves - simple; alternate; edge entire. Outline - long, reverse egg-shape. Apex - pointed, in small…
Leaves - simple; alternate; edge entire. Outline - round heart-shape. Apex - tapering and rather blunt,…
Leaves - simple; alternate; edge entire. Outline - oval or reverse egg-shape. Apex - pointed. Base -…
Leaves - simple; alternate, edge entire. Outline - long oval or long egg-shape. Apex - pointed. Base…
Leaves - simple; alternate; edge entire or lobed. Outline - when the edge is entire usually oval or…
Leaves - simple/alternate; edge somewhat irregularly very sharp-toothed. Outline - rounded, often very…
Leaves - simple/alternate; edge somewhat irregularly very sharp-toothed. Outline - rounded, often very…
Leaves - simple/alternate; edge somewhat irregularly very sharp-toothed. Outline - rounded, often very…
Leaves - simple; alternate; edge with remote, very sharp spine-like teeth, with rounded spaces between.…
Leaves - simple; alternate; edge with remote, not evergreen; egg-shape or long oval, rather thin with…
Leaves - simple; alternate; edge toothed (with the points of the teeth so incurved as to appear blunt),…
Leaves - simple; alternate, or alternate in pairs; edge finely and sharply toothed. Outline - narrow…
Leaves - simple; alternate; edge sharp-toothed. Outline - long oval to reverse egg-shape. Apex - taper-pointed.…
Leaves - simple; alternate; edge distinctly toothed when mature; sometimes near three-lobed Outline…
Leaves - simple; alternate (and in alternate bunches); edge unevenly sharp-toothed (with five to nine…
Leaves - simple; alternate; edge sharply and unequally toothed (sometimes with quite deep and sharp…
Leaves - simple; alternate; edge unevenly sharp-toothed above the middle; sometimes, toward the apex…
Leaves - simple; alternate; edge, sharply toothed above; entire below. Outline - reverse egg-shape.…