Atomic Volume. The volume or space occupied by the atomic weights of gases at a temperature of 60° F., and under a pressure of 30 inches of the barometer, compared with that occupied by one part by weight of hydrogen under the same conditions.
In the same table the most important elements are distinguished by the largest type, those next in importance by medium type, and those of rare occurrence, or of which we know but little, by the smallest type.
ATOMIC WEIGHTS. See Atom.
ATON′IC. Syn. Aton′icus, L.; Atonique, Fr.; Atonisch, Schlaff, Ger. Weak; debilitated; deficient in tone or strength. In pathology, applied to diseases or conditions of the body (ATONIC DISEASES; ATONY) in which debility is the leading feature. In pharmacology, ATONICS are agents which relax or lower the tone of the system.
AT′ONY. Syn. Ato′nia, L.; Atonie, &c., Fr., Ger. In pathology, loss of tone, relaxation, morbid diminution of vital energy or power; commonly applied to debility of any kind.
AT′ROPHY (-fe). Syn. Atro′phia, L.; Atrophié, &c., Fr.; Atrophie, Ger. In pathology, wasting or emaciation, with loss of strength, and unaccompanied by fever or other sensible cause; defective nutrition; decline.
Classif., Causes, &c. It is either local, as in the case of a limb which is small, imperfectly developed, or withered; or general, affecting the whole body. Gen′eral atrophy appears to depend on deficient nutrition, arising from a want of due balance between the functions of assimilation and absorption, or from profuse evacuations draining off the materials necessary for the support of the body. In the former case only may it be regarded as an independent disease. Lo′cal atrophy commonly arises from some cause which lessens the normal circulation of blood in the part; or from a diminution of the nervous influence, as in paralysis. General atrophy is most frequent in infancy, childhood, and old age. In the first two it may be often traced to bad nursing, worms, or a scrofulous taint; and not unfrequently to continually inhaling impure or damp air. In adults, the causes are impaired digestion and imperfect action of the chyliferous organs, and sometimes diseased action of the liver. In many cases it results from the use of tobacco.
Treatm. This consists in a close attention to diet (which should be liberal and nutritious), exercise, clothing, ventilation, warmth, &c., with gentle stimulants, and chalybeate tonics where not contra-indicated; and, in the case of adults, the moderate use of pure generous wine or malt-liquor. Among special remedies, both in this disease and anæmia, may be mentioned pure sweet cod-liver oil, which seldom fails to arrest or greatly retard the progress of the disease, and in very many cases effect an entire cure. When this affection is symptomatic of any other disease, as worms, stomach or liver complaints, &c., the removal of the latter must of course be first attempted. See Anæmia, Chlorosis, Tabes, &c.
ATRO′′PIA (trōpe′y′ă). C34H23NO6. [L.; B. P.] Syn. At′ropine (-pin; sometimes atro′pĭne‡), Eng., Fr.; Atropi′na, Atro′′pium*, L. An alkaloid discovered by Brandes in at′ropa belladon′na or deadly nightshade.
Prep. 1. (B. P. Process.) Take of belladonna-root, recently dried, and in coarse powder, 2 lbs.; rectified spirit, 10 pints; slaked lime, 1 oz.; diluted sulphuric acid, carbonate of potash, of each a sufficiency; chloroform, 3 fl. oz.; purified animal charcoal, a sufficiency; distilled water, 10 fl. oz. Macerate the root in 4 pints of the spirit, for 24 hours, with frequent stirring. Transfer to a displacement apparatus, and exhaust the root with the remainder of the spirit by slow percolation. Add the lime to the tincture placed in a bottle, and shake them occasionally several times. Filter, add the diluted sulphuric acid in very feeble excess to the filtrate, and filter again. Distil off three fourths of the spirit, add to the residue the distilled water, evaporate at a gentle heat, but as rapidly as possible, until the liquor is reduced to one third of its volume and no longer smells of alcohol; then let it cool. Add very cautiously, with constant stirring, a solution of carbonate of potash so as nearly to neutralise the acid, care, however, being taken that an excess is not used. Set to rest for six hours, then filter, and add carbonate of potash in such quantity that the liquid shall acquire a decided alkaline reaction. Place in a bottle with the chloroform; mix well by frequently repeated brisk agitation, and pour the mixed liquids into a funnel furnished with a glass stop-cock. When the chloroform has subsided, draw it off by the stop-cock, and distil it on a water-bath from a retort connected with a condenser. Dissolve the residue in warm rectified spirit; digest the solution with a little animal charcoal: filter, evaporate, and cool until colourless crystals are obtained.