The fruit is a two to many-celled berry with central fleshy placenta and many small kidney-shaped seeds which are densely covered with short, stiff hairs, as seen in Figs.
The fruit of the original species from which our cultivated tomatoes have developed was doubtless a comparatively small two to many-celled berry, with comparatively dry central placenta and thin walls.
One feature common to all living things, from one-celled creatures to complex animals like man, is that they are all composed of microscopic units known as cells.
Mount these two cover-slips on a double-celled slide.
Dilution" consisted in estimating approximately the number of bacteria present in a given volume of fluid (by means of a graduated-celled slide resembling a hæmatocytometer, Fig.
For this is in accordance with the universal law of Growth and Decay--a law that exempts neither the one-celled amoeba, nor the complex Solar system whirling yonder in Infinite space.
A number of years previously Chun had made the discovery that single blastomeres of the Ctenophore egg, isolated at the two-celled stage, gave half-embryos.
Schultze[498] showed that if the frog's egg is held between two plates and inverted at the two-celled stage there are formed two embryos instead of one.
Swammerdam is said to have observed the 2-celled stage in the egg of the frog (Bibl.
Its fruit is a depressed many-celled woody capsule which, when completely dry, bursts with a loud report and scatters the seeds.
Now the single-celled Infusorian is in many respects comparable with the single-celled germ of the higher animals.
But study of a one-celled animal, an Infusorian, for example, reveals that when it reaches a certain age it pinches in two, and each half becomes an Infusorian in all appearance identical with the original cell.
The earliest one-celled protozoa were probably succeeded by many-celled animals of the type of the blastosphere, and these by gastrula-like organisms.
Compare the conditions surrounding a one-celled animal, living in water, to the conditions surrounding the cells in the body.
The forms most frequently seen by such an examination are one-celled plants.
As this is the course of embryonic development, and as it is so well retained in the lowest groups of the many-celled animals, we take it to be the next stage.
The one-celled animal in its shell is, however, no longer a microscopic grain.
We may imagine that the age of microbes was succeeded by an age of these many-celled larger bodies, and the struggle for life entered upon a new phase.
But even a single cell lends itself to infinite variety of shape, and we have to penetrate to the very lowest level of this luxuriant world of one-celled organisms to obtain some idea of the most primitive living things.
Each one-celled unit remains an animal; it is a colony of unicellulars, not a many-celled body.
It is the type to which a moving close colony of one-celled microbes would soon come.
When we had reached this stage in the development of animal life, we found great difficulty in imagining how the chief lines of the higher Invertebrates took their rise from the Archaean chaos of early many-celled forms.
As is well known, the chalk consists mainly of the shells or outer frames of minute one-celled creatures (Thalamophores) which float in the ocean, and form a deep ooze at its bottom with their discarded skeletons.
We can only conclude, from the later facts, that these primitive many-celled plants branched out in several different directions.
For the moment, however, we must glance at the operation of this and other natural principles in the evolution of the one-celled animals and plants, which we take to represent the primitive population of the earth.
In the course of time little one-celled living units appeared in the waters of the earth, whether in the shallow shore waters or on the surface of the deep is a matter of conjecture.
Large numbers of the many-celled bodies shrank from the field of battle, and adopted the method of the plant.
The last-named science teaches us also that a primitive form of soul-activity is already present even in the lowest animals, the single-celled primitive animals, Infusoria and Rhizopoda.
For a long time our planet was inhabited solely by such Protista or single-celled primitive creatures.
In flax (Linum) by the folding inwards of the back of the carpels a five-celled ovary becomes a ten-celled fruit.
In Cathartocarpus Fistula a one-celled ovary is changed into a fruit having each of its seeds in a separate cell, in consequence of spurious dissepiments being produced horizontal from the inner wall of the ovary.
In Astragalus the folding inwards of the dorsal suture converts a one-celled ovary into a two-celled fruit; and in Oxytropis the folding of the ventral suture gives rise to a similar change.
In the oak and hazel, an ovary with three and two cells respectively, and two ovules in each, produces a one-celled fruit with one seed.
In the pomegranate there is a peculiar baccate many-celled inferior fruit, having a tough rind, enclosing two rows of carpels placed one above the other.
The nut or glans is a dry one-celled indehiscent fruit with a hardened pericarp, often surrounded by bracts at the base, and, when mature, containing only one seed.
The teleutospore puts forth on germination a four-celled structure, the promycelium or basidium, and this bears later four sporidia or basidiospores, one on each cell.
If plants and animals all developed from a one-celled animal, such as the amoeba, why did not the amoeba develop?
The amoebae, one celled animals, smaller than a small pin-head, have existed unchanged since life began.
They say that all species developed by growth, but do not explain why we still have the one-celled amoeba, the microscopic bacilli of plant life, and the microscopic species of animal life.
We have the one-celled amoeba, the microscopic animals, and the lowest forms of animal life.
The tonsil is frequently the primary seat of lympho-sarcoma, a very malignant form of round-celled sarcoma.
Epithelioma of the lip# is of the squamous-celled variety, and is met with either as a fungating wart-like projection, or as an indurated ulcer.
All varieties of sarcoma and carcinoma are met with; of the former, the round and spindle-celled are the most common.
Now, let us suppose that we have under our microscope a one-celled animalcule quite as simple in structure as our supposed ancestor.
There is, indeed, the best ground to suppose that the one-celled animals and the embryo-cells referred to, have little in common except their general form.
Multiplication of one-celled animals, 59; of many-celled animals, 61.
As already learned in the examination of examples of one-celled animals, it is evident that life may be successfully maintained without a complex body composed of many organs performing their functions in a specialized way.
From the examination of Hydra we have learned that there are true many-celled animals which are much less complex in structure than the toad and crayfish.
The one-celled animals are called Protozoa, and the many-celled animals Metazoa.
These spores germinate quickly when they fall into water or some organic liquid, and the rapid succession of generations soon gives rise to the hosts of bacteria and one-celled animals which infest all standing water.
All of the animals of the ocean depend upon the marine Protozoa and the marine Protophyta, one-celled plants, for food.
A few many-celled animals will be found in it preying on the one-celled ones.
The many kinds belonging to these orders secrete a tiny shell (of lime in the Foraminifera, of silica in the Radiolaria) which encloses most of the one-celled body.
So our ancestry runs back to the very beginning, when it originated in the one-celled animals which are also the ancestors of all the rest of the animal world.
Between these two extremes we have all degrees, from the innumerable cells that build up the body of the highest Vertebrate to the single-celled Worm, and from the myriad cells of the Oak to the single-celled Alga.
Associated with these, but formed earlier, and germinating immediately, are often to be found large single-celled spores, borne on long stalks.
One of the simplest of the single-celled animals is the Ameba (Fig.
There are enormous numbers of these single-celled animals existing in all parts of the world.
Many other forms might be cited to illustrate reproduction in single-celled animals, whether free or in colonies, but all such cases would be practically but repetitions or modifications of those we have already examined.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "celled" in a variety of sentences. We hope that you will now be able to make sentences using this word.
