. The Pharmaceutical era. ethrough membranes readily. Uncrystallizable, glue-like,or amorphous substances do not diffuse or only withgreat slowness. For the first class Professor Grahamhas proposed the term Crystalloid and for the secondColloid. It is evident therefore that osmose offers amethod of separating crystalloids and colloids from eachother. Pharmaceutical Applications. The Dialyzer.—For the practicalapplication of the principle of osmose to the separationof crystalloids and colloids, an apparatus termed a dialy-zer is employed. This may be of various forms, but acommon one is in the
. The Pharmaceutical era. ethrough membranes readily. Uncrystallizable, glue-like,or amorphous substances do not diffuse or only withgreat slowness. For the first class Professor Grahamhas proposed the term Crystalloid and for the secondColloid. It is evident therefore that osmose offers amethod of separating crystalloids and colloids from eachother. Pharmaceutical Applications. The Dialyzer.—For the practicalapplication of the principle of osmose to the separationof crystalloids and colloids, an apparatus termed a dialy-zer is employed. This may be of various forms, but acommon one is in the shape of a deep hoop, as the rimof a sieve, across one side of which a piece of parchmentpaper is tightly drawn. The material to be separatedis placed in the dialyzer and the latter floated on or sus-pended in water contained in a larger outer vessel. () If, for example, the dialyzer contained an acidified in-fusion of an alkaloidal drug, the salts of the alkaloidwould pass outward through the membrane, and could. thus be obtained by evaporation of the water in theouter vessel, while the colloidal matter of the infusionwould remain in the dialyzer. The process may be made use of by toxicologists toseparate crystalloidal poisonous substances from mix-tures of organic matter which would interfere with theiridentification by chemical tests. The form of the dialyzer is of minor importance. Allthat is necessary is the means of dividing the liquids tobe subject to osmose by means of an appropriate mem-brane. A very efficient dialyzer is the inverted funnelshown in the figure. (Fig. 14.) Osmose plays an important part in the animal econ-omy. It is by this process that the nutrient portionsof the food pass from the intestinal cavity into the bloodvessels, and from the latter to the tissues. In like man-ner, it is by osmose that the tissues discharge theirwaste products back into the blood. Osmose is alsothe method by which the roots of plants absorb materialsfrom the soil, and
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Keywords: ., bookcentury1800, booksubjectdrugs, booksubjectpharmacy, bookyear1
