Agglutination

“ Agglutination is not very practical owing to the frequent absence of agglutinins from the serum of plague patients. Then, too, there is a marked tendency to spontaneous agglutination on the part of the plague bacilli. Strong states that culturing at 37°C. lessens this tendency to spontaneous agglutination. Again, even when present, the titre of plague-agglutinating sera is usually quite low so that one must work with dilutions of from 1 to 10 or 1 to 20. ”

“ Agglutination. serum is that of agglutination. By this is meant the aggregation into clumps of the bacteria uniformly distributed in an indifferent fluid; if the bacterium is motile its movement is arrested during the process. The process is of course observed by means of the microscope, but the clumps soon settle in the fluid and ultimately form a sediment, leaving the upper part clear. ”

“ This conclusion is not justified, as we must suppose that the process of immunization begins to be developed at an early period in the disease, that it gradually increases, and ultimately results in cure. It should also be stated that agglutinins are used up in the process of agglutination, apparently combining with some element of the bacterial structure. In view of all the facts it must be admitted that the agglutinins and immune bodies are the result of corresponding reactive processes, and are probably related to one another. ”

“ Very seldom is there any doubt as to the presence or absence of agglutination. When doubt exists, it is easy to repeat the test and obtain a confirmation of the result. It may perhaps be urged that this test is quite insufficient for eliminating the slighter degrees of incompatibility which have produced serious results when the transfusion has been repeated [107] several times. But in the cases reported, the blood that was used had not shown any agglutination even when most carefully observed under the microscope. ”

“ In the absence of agglutination haemolysis never occurs. Only about one-fifth of agglutinating sera prove also haemolytic. Rarely a pernicious anaemia patient’s serum may agglutinate his own red cells. This auto-agglutination is regarded as an important test in acquired haemolytic jaundice. ”

“ In the absence of any stock sera, the agglutinating test may be applied directly. A few cubic centimetres of blood are taken from the patient, and the serum as soon as it has [102] separated is tested against the corpuscles of the prospective donor. If agglutination occurs, this donor is at once excluded. If no agglutination occurs, he is either of the same group as the patient or belongs to a compatible group. ”

“ These may or may not show agglutination when the result of the examination of the 5 per cent. preparation is positive, according to the potency of the specific serum; and by the examination of a series of dilutions a quantitative comparison of the valency of specific sera from different sources, or of serum from the same animal at different periods during the course of active immunisation may be obtained. ”

“ The protein used as antigen to stimulate its formation, or some part of the protein molecule (haptophore group) , which acts as stimulus to the cell is spoken of as a “precipitinogen,” both terms after the analogy of “agglutinin” and “agglutinogen.” In fact the specific precipitation and agglutination are strictly analogous phenomena. Precipitins act on proteins in (colloidal) solution and cause them to settle out, agglutinins act on substances within cells which cells are in suspension in a fluid and cause the cells to settle out. ”

“ It is very unusual for sera to agglutinate any other bacteria then the specific one in dilutions as high as 1-80.
Macroscopic Agglutination.—For the macroscopical or sedimentation test, take a series of small tubes (3⁄8 × 3 inches) and deposit 1 cc. of salt solution in each of the series. Now, having taken an empty test-tube, drop 4 drops of serum in [518] it and then add 12 drops of salt solution. This approximately gives 1 cc. of a 1 to 4 dilution of the serum. It is more exact to make the 1 to 4 dilution with a graduated pipette. ”

“ In the first place it is possible that the agglutinating power of the serum is rendered ineffective by the dilution which it undergoes when it is mixed with the blood of the recipient. It has been shown, however, by Culpepper that agglutination takes place outside the body with serum diluted up to 1 : 150, a degree of dilution far greater than is ever obtained in a transfusion where the dilution in the patient’s circulation is usually no greater than 1 : 7. ”

“ In this group, the cells are agglutinated by the serum of all the other groups, while their serum contains no agglutinin whatever. These groups never change. They are what you might call the 'finger-prints of the blood.'
“As a baby is developed in the embryo,” Kennedy went on, “the specific agglutinability of the red cells, call agglutinogen, appears first and is usually present at birth. The specific agglutinative power of the blood-serum, called agglutinin, which is to characterize the individual through life, may be absent at birth and may not appear for some months.” ”

“ By diluting the blood serum from the animal to be tested the agglutinins for the related organisms (so-called “coagglutinins” or “partial agglutinins”) will become so much diminished as to show no action, while the agglutinin for the specific organism is still present in an amount sufficient to cause its clumping. Agglutinins are specific for their particular agglutinogens, but since a given blood serum may contain many agglutinins, the serum’s specificity for a given bacterium can be determined only by diluting it until this bacterium alone is agglutinated. ”

“ The substance within the introduced cell which acts as a stimulus (antigen) to the body cells is called an “agglutinogen.” That “agglutinogen” is present in the cell has been shown by injecting animals experimentally with extracts of cells (bacterial and other cells) and the blood serum of the animal injected showed the presence of agglutinin for the given cell. It will be noticed that the receptors which become the free agglutinins have at least two functions, hence at least two chemical groups. ”

“ The glands act as filters, arresting not only inert substances, such as blood pigment circulating in the lymph, but also living elements, such as cancer cells or bacteria. As it passes through a gland the lymph is brought into intimate contact with the leucocytes, and in bacterial infections there is always a struggle between the organisms and the leucocytes, so that the glands may be looked upon as an important line of defence, retarding or preventing the passage of bacteria and their products into the general circulation. ”

“ The proteins of the lens are an excep­tion inasmuch as, according to Uhlenhuth, the proteins of the lens of mammals, birds, and amphibians cannot be discriminated from each other by the precipitin reac­tion.55
7. The serum of certain humans may cause the destruc­tion or agglutina­tion of blood corpuscles of certain other humans. This fact of the existence of “isoagglutinins” seems to have been established for man, but Hektoen states that he has not been able to find any isoagglutinins in the serum of rabbits, guinea-pigs, dogs, horses, and cattle. ”

“ In order that it may exert this power it requires the presence of a substance normally present in the serum known as “complement.” The development of these “anti-bodies,” though it has been studied mainly in connexion with bacteria and their toxins, is not confined to their action, but can be demonstrated in regard to many other substances, such as ferments, tissue cells, red corpuscles, &c. In some animals, for example, the blood serum has the power of dissolving the red corpuscles of an animal of different species ”

“ But in certain directions, notably in regard to the relations with micro-organisms, changes in the blood-plasma can be made out, though they are not associated in all cases with changes in the formed elements which float in it, nor with any obvious microscopical or chemical alterations.
The phenomena of immunity to the attacks of bacteria or their toxins, of agglutinative action, of opsonic action, of the precipitin tests, and of haemolysis, are all largely dependent on the inherent or acquired characters of the blood serum. It is a commonplace thatImmunity. ”

“ The resistance offered by the living stomach of an animal to the dissolving effect of the juice secreted by the stomach itself has to be explained by immunity. A watery solution of pepsin—the digestive principle of the stomach—acidulated by muriatic acid, and thus, as to composition, corresponding to the digesting juice of living animals, upon addition of pieces of the stomach of any mammal, dissolves them, forming a perfect solution. The stomach of the living healthy animal, on the contrary, does not undergo the least change by the secreted juice ”

“ In the operation of a vomit, not only the motions of the stomach and duodenum become inverted, but also those of the lymphatics and lacteals, which belong to them; whence a great quantity of chyle and lymph is perpetually poured into the stomach and intestines, during the operation, and evacuated by the mouth. Now at the same time, other branches of the lymphatic system, viz. those which open on the cellular membrane, are brought into more energetic action, by the sympathy above mentioned, and an increase of their absorption is produced. ”

“ Section IV—Teeth and Gums
There is one source of poisoning and infection so universal as to need special mention. This is infection through the mouth. Considered from the standpoint of efficiency, the modern mouth is out of adjustment with modern conditions—or, perhaps we should say, modern conditions are out of adjustment with it. Notwithstanding the numerous bacteria that flourish within its portals, mouth secretions and the mucous membranes do not seem to have the protecting power which is often manifest in other regions of the body and which protects an animal in a state of nature. ”

“ Within the large intestine bacterial action goes on fully as vigorously as in the small, and because of the smaller relative amounts of digestible food and of water a much larger proportion of the intestinal contents consists of the bodies of the bacteria and of the products of their metabolism. Since the sugars have been completely absorbed out by the time the food reaches the large intestine and the remaining materials upon which the bacteria can feed are more largely of the protein class, the bacterial action changes from fermentation to that which we commonly describe as putrefaction. ”

“ The known mechanisms for this in the body are ameboid cells, especially the phagocytes. It is most probable that these are the chief agents in getting bacteria into the tissues through various free surfaces. The phagocytes engulf bacteria, carry them into the tissues and either destroy them, are destroyed by them, or may disgorge or excrete them free in the tissues or in the blood.
DISSEMINATION OF ORGANISMS.
Dissemination of organisms within the tissues occurs either through the lymph channels or the bloodvessels or both. ”

“ Certain other diseases, such as cholera, give a similar specific serum reaction with their specific organisms. These sera have, in addition, a slight common action—a general agglutinating power—which, however, is not manifested except in concentrated solutions, the higher dilutions failing to give any clumping action at all, except with the specific bacillus associated with the disease from which the patient, from whom the serum is taken, is suffering. ”

“ Take your microscope and look at a drop of fluid from the mouth, the gums, the throat, the stomach, the bowels, and you will find it simply swarming with bacteria, bacilli, and cocci, each species of which numbers its billions. There are thirty-three species which inhabit the mouth and gums alone! We are literally alive with them; but most of them are absolutely harmless, and some of them probably slightly helpful in the processes of digestion. ”

“ Though in man infection through wounds is the readiest way of receiving the disease, the bacillus may also obtain access through the digestive organs, the lungs and mucous membranes of the eyes, nose and lips. ”

“ The nerve ganglia that lie in the walls of the intestines can be influenced mechanically by the contents of the intestines, when such are bulky, and also when they are fermenting; therefore, the bacteria, by promoting fermentation, also aid in peristalsis. The bulky condition of the bowel contents can be best induced by food of the vegetable kingdom through its cellulose contents, of which tissue the cells of plants or fruits are largely formed. When these irritating agents act on the nerve filaments in the intestines, the bowel will contract and expel its contents. ”

“ We have shewed before how the Mass of the Blood becomes impregnated with a saline Acrimony, more or less Acid, from a sharp and indigested Chyle, and the Powers of Digestion weakned and impaired; whence is easily explained how the Lymph and acrid Serum is communicated to the mucilaginous Glands, and the smallest Branches of the Arteries, so as to infect and coagulate the Mucilage, in Proportion to the Quantity of Salts they contain. ”

“ Luxuriant cultures of the desired organism are grown upon inclined agar; the growth is then removed with salt solution and a glass rod, and thoroughly emulsified by shaking in a test-tube, in order to get the germs well distributed and the clumps broken up. The number of germs in a given quantity of the emulsion is then determined by comparing the number of germs and red blood-corpuscles in a mixture of one part emulsion, one part freshly drawn blood, and three parts of normal salt solution. ”