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He knew no more than a firefly about rays or about race or sex or ennui or a bar of music or a pang of love or a grain of musk or of phosphorus or conscience or duty or the force of Euclidian geometry or non-Euclidian or heat or light or osmosis or electrolysis or the magnet or ether or vis inertiae or gravitation or cohesion or elasticity or surface tension or capillary attraction or Brownian motion or of some scores, or thousands, or millions of chemical attractions, repulsions or indifferences which were busy within and without him; or, in brief, of Force itself, which, he was credibly informed, bore some dozen definitions in the textbooks, mostly contradictory, and all, as he was assured, beyond his intelligence; but summed up in the dictum of the last and highest science, that Motion seems to be Matter and Matter seems to be Motion, yet "we are probably incapable of discovering" what either is.
Osmosis, or diffusion through a septum, is a phenomenon which has been known for some time. The discovery of it is attributed to the Abbé Nollet, who is supposed to have observed it in 1748, during some "researches on liquids in ebullition." A classic experiment by Dutrochet, effected about 1830, makes this phenomenon clear.
Under these conditions some of the sugar solution passes through the bag into the water, and some of the water passes from the vessel into the bag. The force here concerned is a force known as osmosis or dialysis, and is always exerted when two different solutions of certain substances are separated from each other by a membrane.
The proper procedure in these circumstances is first properly to reduce the blood pressure, or what I have, quoting Hare, ventured to call the over plus pressure. The relation of osmosis, lymphagogue activity, absorption of edema, capillary contractility and decreased affinity of ocular colloids for water to the reduction of increased intra-ocular tension.
But they all agree in certain characters; all take their food and oxygen and carry on excretory processes by osmosis, i.e., through the body-wall; all are capable of some kind of locomotion, some have one or more flagella, others move by a pseudopod movement. Some are capable of moving from cell to cell in the body as do the white blood-corpuscles.
"Then he might have absorbed it from the water," I insisted, recalling a recent case of Kennedy's and adding, "by osmosis." "You saw how difficult it was to dissolve in water," Craig rejected quietly. "Well, then," I concluded in desperation. "How could it have been introduced?"
The interchange of material between the blood and the lymph, and the lymph and the cells, takes place in part according to the principle of osmosis. *Exercises.*—1. Explain the necessity for the lymph in the body. Compare lymph and water with reference to density, color, and complexity of composition. Compare lymph and blood with reference to color, composition, and movement through the body.
In solving this question, he considered himself justified in drawing conclusions from the manner in which such compounds behaved toward dead animal membrane. If any kind of osmosis could take place, he argued, from ointments prepared with vaseline, etc., through dead membranes, such osmosis would most probably also take place through living membranes.
We must notice, however, that the physical force of osmosis is not the only factor concerned in absorption. In the first place, it is found that the food during its passage through the intestinal wall, or shortly afterwards, undergoes a further change, so that by the time it has fairly reached the blood it has again changed its chemical nature.
The answer to this question has been furnished by biologists, at which we cannot be surprised. The phenomena of osmosis are naturally of the first importance in the action of organisms, and for a long time have attracted the attention of naturalists.
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