Whether bacteria will be destroyed or not after they have been ingested by the leucocytes will depend upon the digestive powers of the latter, and these probably vary in different species of animals.
Thus the apparent increased activity of the leucocytes is due to a preliminary effect of the opsonins on the bacteria.
The number of bacteria contained within a number of, say fifty, leucocytes can be counted and the average taken.
The average number of bacteria contained within leucocytesin the case tested, divided by the number given by the normal serum, is called the phagocytic index.
While in immunity there probably occurs no marked change in the leucocytes themselves, it must be admitted that the increased destruction of bacteria by these cells is of the highest importance.
Evidence has been brought forward within recent years that the leucocytes may constitute an important source of the antagonistic substances which appear in the serum.
As regards the former, leucocytesare guided chiefly by chemiotaxis, i.
Find the edge of the blood film--along this the bulk of the leucocytes will be collected.
The fine rod-shaped granules of the polymorphonuclear leucocytes are usually very faintly stained.
The granules of the polymorphonuclear leucocytesstain oxyphile.
The granules of those cells which correspond to polymorphonuclear leucocytes are rod-shaped, but smaller and finer than in the fowl, and do not show clubbed appearances.
The minute neutrophile granules of the polymorphonuclear leucocytes are often very scanty, and sometimes apparently absent.
The polymorphonuclear leucocytes have only a few very minute coccal-shaped oxyphile granules, the nucleus is polymorphous.
Next distribute the leucocytes evenly throughout the mass of red cells by rotating the tube between the palms of the hands--just as is done with a tube of liquefied medium prior to pouring a plate.
Remove the supernatant saline solution as nearly down to the level of the leucocytes as can be safely done without removing any of the leucocytes.
The granules of the cells corresponding to the polymorphonuclear leucocytes are rod-shaped, often beaded or with clubbed ends.
The polymorphonuclear leucocytes are large cells, about 20µ; no definite granules can be observed.
The cells probably corresponding to eosinophile leucocyteshave fine coccal-shaped granules, faintly staining eosinophile or neutrophile.
The granules of the polymorphonuclear leucocytes are usually not stained, or only very faintly so.
Saenger also discovered that in pernicious leucemia the leucocytes of the mother are not present in the fetal circulation.
Delicate tests for albumin are used by men who find these high averages, as a few leucocytes from leucorrhoea will give the reaction.
At first the walls of the vessels are reddish from congestion, succulent, and swollen, infiltrated by leucocytes and inflammatory exudation and the cellular elements undergoing proliferation.
There are also eight thousand leucocytes or colorless cells in a cubic millimeter of blood, this giving a total number of four billion in the average adult, and these vary in character and in relative numbers (Fig.
Again, not all inclusion of bacteria withinleucocytes is indicative of phagocytosis; in many cases the bacteria seem to find the best conditions for existence within the leucocytes, and these and not the bacteria are destroyed.
The migration of leucocytes from the vessels takes place chiefly on the side towards the cornea, and the migrated cells make their way along the devious tracts of the communicating lymph spaces to the area of injury.
The studies were carried further into the diseases of the higher animals, and it was found the leucocytes in these played the same part as did the cells in the body cavity of the daphnea.
The numbers present depend much upon the character of the agent which has produced the injury, and they may be more numerous than the ordinary leucocytes which migrate from the blood vessels.
In many cases, however, those penetrating became enclosed in cells which the body cavity contains and which correspond with the leucocytes of the blood; in these the spores were digested and destroyed.
Large numbers ofleucocytes which give protection by phagocytosis are constantly passing to the surface, and there is also a constant stream of fluid towards the surface.
Such natural immunity seemed to be unconnected with defence by phagocytosis, for the leucocytes of the animal might or might not have phagocytic reaction to the particular organisms to which the animal was immune.
The leucocytes as free moving cells also come under the influence of such tropisms.
The presence in the injured part of bacteria or of injured and dead cells exerts an attraction for the leucocytes within the vessels causing their migration.
In addition to their function as filters the lymphatic glands are probably one of the sources from which the leucocytes are derived.
Again, besides discharging fluid and dissolved material into the tissue spaces, the blood may also discharge leucocytes, and under many conditions this emigration of leucocytes may be very extensive.
If this occurs we know that the damaged cells are destroyed and their debris removed either by digestion by leucocytes or by disintegration and solution.
For the men of the Explorer, a week's cure with deep melting to de-differentiate the leucocytes and turn them back to normal tissue, then regrowth and reforming from the cells that were there.
The leucocytes of tall, red-headed people, finding no strangeness in the bloodstream of any of the tall, red-headed people.
There was no sign of a micro-organism in anyone's blood, merely a growing horde of leucocytes and phagocytes, prowling as if mobilized to repel invasion.
Leucocytes can run through several thousand generations of evolution in six months," Pat Mead finished.
Mead cells contagious from one to another, not a disease attacking or being fought, but acting as normal leucocytes in whatever body they were in!
On the other hand, it died if the same doses of the same salt had been protected from the leucocytes by an elderberry bag, or when the leucocytes had been attracted elsewhere by a previous injection of carmine for instance.
On the other hand, if, in the same medium, some exudate is injected containing damaged leucocytes from which the digestive juice is leaking, the vibriones introduced are destroyed.
This is the organ par excellence which takes up the solid carmine-grains and bacilli, and apparently, from Kowalewsky's description, contains leucocytes in large numbers.
Raja batis have noleucocytes in the blood or elsewhere.
In all cases he finds that a phagocytic action with respect to solid {421}bodies is a property of the leucocytes, and that these leucocytes which are found in the coelomic spaces of the Annelida, etc.
Such formation of leucocyteshas been especially described in connection with the lining epithelium of the coelomic cavities, as stated in Chapter XII.
The evidence, then, is very strong that in the Crustacea and Arachnida the original segmental excretory organs do not disappear, but remain as ductless glands, of the nature of lymphatic glands, which supply leucocytes to the system.
Finally, he points out how necessary it is that we should respect the integrity of the leucocytes in the presence of microbic infections or intoxications.
The Toxine Alcohol," which deals with leucocytesand their functions.
Of this he says:-- "The antagonism of alcohol to the fundamental functions of life is further exhibited by its action on the cellular elements of living tissues and the free cells or leucocytes of the blood.
So long as the leucocytes can make their way to this mass, and shut it off from the surrounding tissue, so long we shall have no extension of the abscess.
Among the more recent findings of science in regard to the effects of alcohol are the action of this drug upon the leucocytes or "guardian cells" of the body.
Alcohol, in even relatively moderate quantities, irritates the kidneys, so that the exudation of leucocytes and the formation of cylindrical casts may occur.
He found that the alkalinity of the blood was slightly diminished, and the number of leucocytes somewhat decreased.
We see at once the part that the leucocytes play in attacking micro-organisms, and of localizing their action.
Then a little distance away from the toxin and toxin-forming organisms, the leucocytes are coming up in large numbers, forming a sort of protecting army, as it were.
When Metchnikoff believed he had discovered that the leucocytes in the blood absorb and digest microbes and thus save man from infection, it seemed as if a ray of clear and simple light had illuminated all the mystery.
It is probable that the sensitive and travelling leucocytes of our invertebrate ancestors have powerfully co-operated for millions of years in the phylogenesis of the advancing animal organisation.
It has been shown by the discoveries of the last few decades that these leucocytes are of the greatest physiological and pathological consequence to the organism.
Though the relative proportions of the leucocytes are probably continually undergoing change even in health, especially as the result of taking food, the number of red corpuscles remains much more constant.
The disease in which the number of leucocytes in the blood is greatest is leucocythaemia or leucaemia.
It constitutes about 4% of all the leucocytes and is highly amoeboid and phagocytic.
The difference lies in the kind of leucocytes present in excess in the blood, blood-forming organs and deposits in the tissues.
Not only does the clotting process start from the layers containing the leucocytes and platelets, but in them it also proceeds more quickly.
If glycogen is present in solution in the plasma it is there in very small quantities only, and has probably arisen from the destruction of the white blood corpuscles, since some leucocytes undoubtedly contain glycogen.
In human blood the following varieties of leucocytes may be distinguished:-- 1.
The lowermost of these contains chiefly the red corpuscles, the second layer may be grey owing to the high percentage of leucocytes present, while a third, marked by opalescence only, may be very rich in platelets.
The number and nature of the leucocytes in the blood bears no constant or necessary relation to the number or condition of the red corpuscles, and their variations depend on entirely different conditions.
An exception to these two fundamental rules is found in the single case of the leucocytes or white globules of the blood.
The leucocytesare capable of adapting themselves to conditions different from those in which they usually live, provided the change is not too abrupt.
These phagocytes or leucocytes are the nomadic elements of our economy.
After two or three hours we can see the leucocytes grouped around the bubbles.
At other times, and more rarely the isolated leucocytes are not able to absorb the incorporated matters.
The faculty possessed by the leucocytes of seizing solid corpuscles coming in contact with them, inglobing them, and absorbing them, or, as M.
And when the fecundity of these is exhausted the leucocytes come in to occupy the vacated situations, and conduct the organism thus patched up through a senile degeneracy to natural death.
The leucocytes collect around these residues so thickly as sometimes to fuse themselves into a solid mass, a sort of plasmodium or giant cell which digests the debris.
When the provision of air is exhausted, several hours afterward, the leucocytes will cease to move and become inert.
The leucocytesare not always victorious over the microbes, and when these excel in numbers or force it sometimes comes to pass that they are overcome and succumb.
All solid bodies that pass within reach of the leucocytes are seized and incorporated by them, provided they are small or inert enough to be enveloped.
The study of the mechanism by means of which the leucocytes traverse the tissues is very interesting.
The coloring matter of the blood frequently gives rise to insoluble ferruginous deposits which the leucocytes have to convey to the digestive tube.
There is an increase in the number of leucocytes in the cerebro-spinal fluid, and organisms also are found in the fluid.
This clot is soon permeated by newly formed blood vessels, and by leucocytes and fibroblasts, the latter being derived from proliferation of the cells of the marrow and periosteum.
Ingenious methods for determining the influence in vivo of antiseptics on the activities of leucocytes have been worked out by Col.
It is a regular phenomenon to observe activity of the leucocytes obtained from wounds which have been recently treated with hypochlorites.
An important method of judging of the injurious action of antiseptics is to investigate the condition of the leucocytes in wounds recently treated with the substance under consideration.
Consequently, we seem to have strong evidence that peptones are not prone to direct alteration of any kind by the leucocytes of the lymphatic system.
Thus, the view originally advanced by Hofmeister,[221] in which special stress is laid upon the functional activity of the leucocytes of the adenoid tissue surrounding the intestine, demands some consideration.
In apparent harmony with this view is the fact that the leucocytes in the adenoid tissue of the intestine are greatly increased in number during digestion.
There are, indeed, many facts which are plainly opposed to any marked absorption and transformation of peptones by the leucocytes of the intestinal mucous membrane.
In harmony with this view, Pohl finds that there is a much larger number of leucocytes in the blood and lymph flowing from the intestine of an animal in full digestion, than in the arterial blood coming to the intestinal tract.
In this connection we may note the experiments of Horbaczewski,[225] which show that nuclein administered to a healthy man will give rise to a very marked increase in the number of leucocytes in the blood.
The glomerular capsules are much distended, and numerous leucocytes are discernible throughout the organ.
It follows that we must understand that there are two phases in the action of venoms: one negative, when the dose absorbed does not injure the leucocytes; the other positive, when the leucocytes are destroyed.
Delezenne, on his part, has established the existence in snake-venoms of a kinase analogous to the kinase of leucocytes and enterokinase.
According to the observations of Zahn, the nucleus of certain thrombi is the result of the death of these leucocytes and their accumulation upon an altered intima.
Both varieties may result from the enlargement of leucocytes by fusion or by the assimilation of nutriment.
When there are but few leucocytes the deposit is a network of fibrillæ (croup).
The leucocytes may return to the blood-vessels or enter the lymphatics; the latter course probably being the one taken by the larger number of the corpuscles.
The rapid decrease of red blood-cells and a moderate increase of leucocytes were demonstrated by Bouchut and Dubrisay, but the disproportion was not such as to necessitate the diagnosis of leucocythæmia.
The exudation contains not only dead leucocytes and interlacing fibres, but is also provided with abundant granular material, much of which presents the well-known peculiarities of microscopic organisms.
Arnold represents the most strenuous advocates of the stomata theory, according to which the leucocytes pass through canals normally existing in the wall.
Except in the mildest cases the Schneiderian membrane also participates in the inflammation as the disease advances, so that a thin, irritating discharge, containing leucocytes or pus-cells, flows from the nostrils.
But he does not say why it is that there is no such coagulation in suppurative processes, where the leucocytes are more numerous.
In this way the eosinophile granules of the leucocytes and the red corpuscles, are stained by the eosine, while the nuclei of the leucocytes are stained by the methyl blue.
By this means the leucocytes are removed, and the structure of the adenoid tissue itself becomes more evident.
The nuclei of the leucocytes may be stained rapidly in a couple of minutes in a one per cent.
The leucocytes direct their course through the tissues to the chief points of inflammation by reason of chemotaxis, and surround the dead tissues, or any point of bacterial growth, or any foreign body which may be the cause.
Phagocytosis--the power of destruction and removal of bacteria supposedly possessed by the leucocytes emigrating from the blood vessels--explains it in part.
The wandering leucocytes form the pus cells, and if they are very numerous, they constitute a purulent or suppurative inflammation.
The leucocytes surround any foreign body, and if the particles are small enough, they incorporate them within themselves, in fact, they may be said to swallow them.
In this way, the leucocytes are able to pass through the interstices between cells, or along narrow channels in the tissues.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "leucocytes" in a variety of sentences. We hope that you will now be able to make sentences using this word.
