n. fld>(Med.) Of or pertaining to anaphylaxis; caused by anaphylaxis. [ PJC ]

n. fld>(Med.) Shock resulting from anaphylaxis{ 2 }. It is a severe form of physiological shock, often having a fatal outcome, and is caused by an extreme immunological reaction to antigens. It is characterized by smooth muscle contraction and capillary dilation throughout the body, initiated by antibodies of the IgE class. It is usually seen when an antigen to which a person has become hypersensitized is injected intravenously or subcutaneously. It is also called generalyzed anaphylaxis or systemic anaphylaxis, and sometimes anaphylaxis. [ Stedman ] [ PJC + AS ]

pos>n. [ Gr. &unr_; to exchange; kata` wholly + &unr_; to change. ] The science of exchanges, a branch of political economy. [ 1913 Webster ]

a. [ Gr. &unr_; milky, fr. &unr_;, &unr_;, milk. See Galaxy, and cf. Lactic. ] 1. Of or pertaining to milk; got from milk; as, galactic acid. [ 1913 Webster ]

2. Of or pertaining to the galaxy or Milky Way. [ 1913 Webster ]

Galactic circle (Astron.), the great circle of the heavens, to which the course of the galaxy most nearly conforms. Herschel. --
Galactic poles, the poles of the galactic circle. [ 1913 Webster ]

a. [ L. lac, lactis, milk: cf. F. lactique. See Lacteal, and cf. Galactic. ] (Physiol. Chem.) Of or pertaining to milk; procured from sour milk or whey; as, lactic acid; lactic fermentation, etc. [ 1913 Webster ]

Lactic acid (Physiol. Chem.), a sirupy, colorless fluid, soluble in water, with an intensely sour taste and strong acid reaction. There is one center of optical activity, and this results in the observation of three isomeric modifications all having the formula C3H6O3; one is dextrorotatory (L-lactic acid), the other levorotatory (D-lactic acid), and the third an optically inactive mixture of the first two (DL-lactic acid); chemically it is 2-hydroxypropanoic acid. Sarcolactic acid or paralactic acid occurs chiefly in dead muscle tissue, while ordinary lactic acid (DL-lactic acid) results from fermentation, such as the fermentation of milk by lactic acid bacteria. The two acids are alike in having the same constitution (expressed by the name ethylidene lactic acid), but the latter is optically inactive, while sarcolactic acid rotates the plane of polarization to the right. The third acid, ethylene lactic acid, accompanies sarcolactic acid in the juice of flesh, and is optically inactive. --
Lactic ferment, an organized ferment (Bacterium lacticum or Bacterium lactis), which produces lactic fermentation, decomposing the sugar of milk into carbonic and lactic acids, the latter, of which renders the milk sour, and precipitates the casein, thus giving rise to the so-called spontaneous coagulation of milk. --
Lactic fermentation. See under Fermentation. [ 1913 Webster +PJC ]

a. [ Pref. para- + lactic. ] (Physiol. Chem.) Designating an acid called paralactic acid. See Lactic acid, under Lactic. [ 1913 Webster ]

{ } a. [ Cf. F. parallactique. ] Of or pertaining to a parallax. [ 1913 Webster ]

n. [ Cf. F. prophylactique. ] (Med.) A medicine which preserves or defends against disease; a preventive. [ 1913 Webster ]

{ , a. [ Gr. &unr_;, fr. &unr_; to guard against; &unr_; before + &unr_; to guard: cf. F. prophylactique. ] (Med.) Defending or preserving from disease; preventive. Coxe. [ 1913 Webster ]

a. [ L. saccharon sugar + lac, lactis, milk. ] (Chem.) Of, pertaining to, or designating, an acid now called mucic acid; saccholic. [ Obs. ] [ 1913 Webster ]

a. [ Sarco- + lactic. ] (Physiol. Chem.) Relating to muscle and milk; as, sarcolactic acid. See Lactic acid, under Lactic. [ 1913 Webster ]

{ } a. (Geol.) Stalactitic. [ 1913 Webster ]