Endosmosis

“ This of course was simply the effect of endosmosis. Mr. Couch, in describing the moulting of the common Edible Crab (Cancer Pagurus) , speaks of its drinking large quantities of water, and thus becoming distended; but I rather think that the distension takes place by endosmosis, even during life. There are two circumstances which militate against Mr. Couch's opinion:—first, the rapidity with which the distension occurred in the Crab I have just exhibited, while still in the act of moulting ”

“ Now, Dutrochet had before observed that if the positive pole of a battery be inserted in the pure water, and the negative pole in the gum-water, the acts of endosmosis are effected more energetically. Oniraus and Legros discovered further, that, if the contrary arrangement be adopted, that is, if the positive pole be placed in the gum-water, and the negative pole in the pure, the level of the liquid in the tube descends noticeably, instead of rising. Electricity, therefore, can reverse the usual laws of endosmosis. ”

“ Plants absorb their food entirely in a liquid or gaseous form, by imbibition, according to the law of endosmosis, through the walls of the cells that form the surface; as when liquids of unequal density are separated by a permeable membrane, the lighter liquid or the weaker solution will flow into the stronger with a force proportionate to the difference in density ”

“ Here is our Opalina, for example, without mouth, or stomach, or any other organ. It is an assimilating surface in every part; in every part a breathing, sensitive surface. Living on liquid food, it does not need a mouth to seize, or a stomach to digest, such food. The liquid, or gas, passes through the Opalina’s delicate skin, by a process which is called endosmosis; it there serves as food; and the refuse passes out again by a similar process, called exosmosis. This is the way in which many animals and all plants are nourished. ”

“ Urine in health is lower, but in diabetes often much [Pg 76] higher. The production of these secretions, differing in density from the serum of blood, would be inconsistent with the first law of endosmosis. Lastly, we find that in many known cases the theory which I am contesting does not hold good. Seidlitz water and sea-water are both known to be purgative. In both the specific gravity is below that of the serum of blood.
The first, according to Bergmann, has a density of 1.006. It contains in each pint 192.8 grains of solid matter. Out of this, 180 grains consist of Sulphate of Magnesia. ”

“ This ascending sap is not so viscid a liquid as that contained in the cells: thus, the syrupy contents of the latter must, according to the principle of endosmose described in a previous article, absorb into the cells the ascending sap, in a way similar to that whereby syrup placed in a bladder, immersed in a basin of water, will attract the latter liquid through the membrane, until the bladder be filled. While the sap continues to ascend, therefore, the cells must necessarily continue swollen in proportion to their size. ”

“ Important changes take place in the kidneys. They consist essentially in a granular and fatty degeneration of the tubular epithelium, whence the altered appearance of the cortex. Multitudes of bacteria crowd the pyramids. Ecchymoses also are found in the mucous membrane of the pelvis of the kidney, in the bladder, and indeed all along the genito-urinary tract.
The muscular tissue of the heart is in a state of acute fatty degeneration, beginning with a granular change which may at the outset be of very limited extent and involve but few fibres. ”

“ Now, a plant growing in the ground is similarly circumstanced to the bladder in this experiment: its roots furnished with extremities of spongy membrane are interposed between thin water and carbonic acid externally, and a syrupy solution of sugar and gum internally. Now, under those circumstances we need not be surprised if an endosmose should operate, abundantly sufficient to elevate the sap with a force even greater than that determined by Hales.
The use of the ascending sap in the vegetable economy is the last subject which we shall consider in this article. ”

“ Thus it is essential that there should be constantly passing through the organism a flushing, as it were, of fluid, to hold in solution and wash away the products of disassimilation and waste. Those who do not recognise the fact that 3⁄4 of the entire organism is normally composed of fluid cannot fully realise the great need which exists for a copious supply. If there be not a sufficient endosmose, the exosmose must be restricted, and effete matters, soluble in themselves, but not dissolved because of the deficiency of fluid available, will be retained. Take, for example, the uric acid ”

“ Bulk endosomes could be the direct source of SVs, or they may first fuse back to the plasma membrane from which new SVs could then bud by CME. To discriminate between these possibilities, cultures of all four genotypes were exposed to CTX-HRP only during the recovery phase, following a 90 s stimulus, and then analyzed at the 10 and 30 min time points (Figure 1B, Figure 2E–H) . In these samples, only very few large vacuoles were HRP labeled (Figure 2G,H) , indicating that bulk endocytosis occurs nearly exclusively during the high K+ stimulation. ”

“ When transudations are unhealthy, they may accumulate in serous cavities or in cellular structures, and constitute dropsy. Exudation is the result of inflammation, and the product effused coagulates and becomes the seat of a new growth of tissue. Exosmosis means the passage of fluid from within outward, and is a process constantly taking place in health; while transudation takes place because the blood is watery and the tissues are feeble and permeable, permitting the serum and watery elements of the blood to pass into certain cavities, where they accumulate. ”

“ The digested food is carried down the alimentary canal in a purely mechanical fashion by muscular action, and when it reaches the intestine it begins to pass through its walls into the blood. In this absorption we find engaged another set of forces, the chief of which appears to be the physical force of osmosis. The force of osmosis has no special connection with life. If a membrane separates two liquids of different composition (Fig. i) , a force is exerted on the liquids which cause them to pass through the membrane, each passing through the membrane into the other compartment. ”

“ The tenth objection to using an enema is in being obliged to use it from the fact of having such a disease as chronic inflammation of the rectum and colon. Every victim hates to be compelled to do a thing, and the victim of proctitis and colitis is no exception to the rule. In fact, he is beginning to realize that unless he uses it his system will be poisoned by the absorption of the sewage waste. Let the victim object to the disease that necessitates the use of the enema and he will shortly be well. ”

“ If you substitute solid particles, or things that will not dissolve, you will find no change. This property which membranes, such as a bladder, have, is called osmosis. It is by osmosis chiefly that the raw, nourishing material in the blood gets into the flesh lying about the capillaries. It is by osmosis chiefly that food gets out of the stomach into the blood. It is by this property that the worn-out materials are drained away from the blood, and so cast out of the body. By osmosis the blood nourishes and purifies the flesh. By osmosis the blood is itself nourished and kept pure. ”

“ Were it not for the usual presence of granular tissue on a chronically inflamed mucous membrane and for ulcerated sections or patches, channels, and stretched or pouched mucous membrane called piles, the proper use of hot water alone would in time effect a total cure in almost every case of proctitis.
Many well-meaning persons conceive the idea that, if hot water is so beneficial, they may use it as hot as possible for the purpose of an enema likewise, since they will thereby not only relieve the bowels of their stored feces but simultaneously do the inflamed tissues “a whole lot of good.” ”

“ Well, when a man of his age—he'd be near fifty—begins to ask questions, he's rather worse than a child who wants to know where Heaven is or some such thing—for you can't put him off as you can the child. Somewhere or other he'd picked up the word "osmosis," and seemed to have some glimmering of its meaning. He dropped the molecules, and began to ask me about osmosis.
"It means, doesn't it," he demanded, "that liquids will work their way into one another—through a bladder or something? Say a thick fluid and a thin: you'll find some of the thick in the thin, and the thin in the thick?" ”

“ Fig. 31—Vessel with an upright membranous partition for illustrating osmosis. Osmosis.—The term "osmosis" is used to designate the passage of liquids through some partition which separates them. Thus, if a vessel with an upright membranous partition be filled on the one side with pure water and on the other with water containing salt, an exchange of materials will take place through the membrane until the same proportion of salt exists on the two sides (Fig. 31) . The cause of osmosis is the motion of the molecules, or minute particles, that make up the liquid substance. ”

“ He does not seem able to escape from his enemies anywhere.
The mucous membrane lining the orifices of the body is nothing more than the skin turned in to line canals for air, gases, liquids, and solids to pass in and out in order to keep up the physio-logical functions of the body. Very rarely, indeed, do we find, from childhood to old age, the orifice of the intestinal sewer otherwise than chronically inflamed, the invasion extending, moreover, the whole length of the rectum for some distance into the sigmoid colon. ”

“ The best understood relies on a protein called clathrin, and is thought to be essential for nervous system function. Recently, however, a mechanism of vesicle membrane endocytosis that does not involve clathrin was identified. This mechanism, called bulk endocytosis, involves reinternalizing large regions of the cell plasma membrane to generate large compartments called vacuoles, from which new synaptic vesicles eventually form. This mechanism has been observed when neurons fire at high frequency. ”

“ All mechanical obstructions to the free transit of blood through the heart, lungs, or liver are followed by the same results. A free secretion of mucus into the stomach is one of the most commonly recognized. It is often vomited in large quantities. This alkaline mucus, while it dilutes the digestive juices of the stomach, furnishes favorable conditions for the development of low micro-organisms, which contribute to the fermentative process. We may not duly estimate the effects of these organisms on a mucous membrane softened by long-continued passive hyperæmia. ”

“ The amount of fluid which may be secreted by a loop of intestine isolated from the body is limited by the absence of the blood supply. The loop, as shown above, secretes a certain amount of fluid in the first 10 or 20 minutes. If it is then emptied, usually no more fluid appears. The quantity secreted depends on the amount of fluid contained in the intestinal walls at the time of its removal from the body. No fluid passes from the solution in which the loop is suspended into the lumen of the loop; no current is established through the walls from the outside inwards. ”

“ In this way the quantity of fluid injected could be accurately measured and controlled. The salt solution after passing through the long tube reached the ear at approximately body temperature. It is of the greatest importance to protect the intestinal loops in every way possible from loss of heat or from drying.
In the above experiment the intestinal glycosuria, if such a term may be applied to this phenomenon, appears under circumstances which are exactly the same as those necessary for the production of sugar in the urine by saline infusions. ”

“ To illustrate this, let us suppose a bladder containing a little syrup, and placed in a vessel of water, and we will have the conditions necessary for endosmose: the syrup and water will both pass through the bladder in opposite directions, but a greater quantity of water will pass into the syrup, than of the latter into the water. It will be evident to the reader that this excess of thin liquid passing into the denser will constitute a force or power which will require an equal force to neutralise it ”

“ One of the mysterious processes accompanying digestion, the secretion of free muriatic acid by the coats of the stomach, obtains a probable hypothetical explanation through the same law. Finally, much light is thrown upon the observed phenomena of osmose (the passage of fluids outward and inward through animal membranes) by the fact that the membranes are colloidal. In consequence, the water and saline solutions contained in the animal body pass easily and rapidly through the membranes, while the substances directly applicable to nutrition, which are mostly colloidal, are detained by them. ”

“ Abstract The exocytosis of synaptic vesicles (SVs) elicited by potent stimulation is rapidly compensated by bulk endocytosis of SV membranes leading to large endocytic vacuoles (‘bulk’ endosomes) . Subsequently, these vacuoles disappear in parallel with the reappearance of new SVs. We have used synapses of dynamin 1 and 3 double knock-out neurons, where clathrin-mediated endocytosis (CME) is dramatically impaired, to gain insight into the poorly understood mechanisms underlying this process. ”

“ SVs reformed from bulk endosomes can undergo exocytosis upon stimulation. (A) Control (Dyn3 KO) and Dyn1/3 DKO neurons were stimulated by a 90 s high K+ stimulation in the presence of HRP, rested for 30 min in the absence of HRP and then subjected to a second round of high K+ stimulation and recovery, always in the absence of HRP. Loss of HRP-labeled SVs during the second stimulus, and the subsequent recovery of unlabeled SVs, demonstrates that vesicles generated from bulk endosomes are functional SVs. ”