ILLUMINATOR 



604 



IMMUNITY 



are reflected or refracted from the object itself. I. of 

 Eye, the lighting up of the interior of the eye by 

 means of the ophthalmoscopic mirror. I., Oblique, 

 in microscopy, an illumination produced by throwing 

 the rays of light upon an object at any angle of inclina- 

 tion. In ophthalmology, oblique illumination of the 

 cornea consists in focusing a pencil of rays obliquely 

 upon the part. 



Illuminator (il-oo' ' -min-a-tor) [illuminare, to make 

 light]. In microscopy, an optic apparatus for con- 

 centrating light. I., Abbe, an illuminating apparatus 

 for the microscope designed by Professor Abbe. Abbe's 

 Condenser. 



Illuminism (il-oo f -min-iznt) [illuminare, to make 

 bright]. Insane exaltation; especially exaltation 

 with belief in one's communion or direct intercourse 

 with supernatural or heavenly beings. 



Illusion \il-lu' -zhun) [illusio, a mocking]. A false or 

 deceptive mental impression. Illusion differs from 

 hallucination in that it is the false interpretation by the 

 mind of a real sensation. The senses are not at fault 

 in case of illusions, and the defective process is purely 

 psychic. The distinction between illusion and halluci- 

 nation is, however, by no means a constant one. 



Illusional (il-lu' '-zhun-al) [illusio, a mocking]. Of 

 the nature of an illusion. 



Illutation {il-lu-ta f -shun) [in, in; lutum, mud]. Treat- 

 ment of disease by the mud-bath. 



Image (im'-aj) [imago, a likeness]. The picture of an 

 object formed by the focused rays of light proceeding 

 from it. I., After. See After-image. I., Diffusion 

 of. See Diffusion. I., Direct, or I., Erect, that 

 of the fundus oculi as seen with the ophthalmoscope, 

 the details of the fundus presenting their natural rela- 

 tions. I., Inverted, that obtained by interposing 

 between the ophthalmoscope and the observed eye a 

 high-power lens ; it is an aerial image at the focus of 

 the lens used. I., Real, that made by the focused re- 

 flected rays. I., Refraction, an image due to the 

 refraction of light upon entering and leaving an object. 

 Two things are involved :, I. The form of the object. 

 2. The relative refractive power of the object and the 

 mounting-medium. I., Subjective, a photism ; also 

 a visual hallucination. I., Virtual, that produced by 

 the imaginary focus of the rays, as, e. g., behind a 

 mirror. 



Imaginal [im-aj' '-in-al) [imago, an image]. Pertain- 

 ing to the Image, q. v. I. Discs, in entomology, the 

 name given by Weismann to curious encapsulated 

 groups of embryonal cells, connected with the nerves 

 .and nerve-centers of certain insect larvae (Diptera). 

 They are the rudiments from which the nymph is 

 developed. 



Imagination (im-aj-in-a' -shun) [imaginatio, imagin- 

 ation]. The picture-making power of the mind. 

 The faculty by which one creates ideas or mental 

 pictures by means of the data derived from experience, 

 ideally revivified, extended, and combined in new 

 forms. 



Imago (im-a'-go) [L.; gen., Imaginis\ An image. 

 Also, the final, adult, or reproductive stage of an 

 insect. 



Imbalance (im-bal'-ans) [in, not; bilancia, a balance]. 

 Lack of balance ; lack of the power of keeping the 

 erect position ; lack of muscular balance (as between 

 the muscle of the eyes). 



lmbecile(im / -bes-il ) [imbeci litis, \veak~\. Feeble in mind. 



Imbecility (im-bes-il'-it-e) [imbecillitas, imbecility]. 

 Mental weakness or defect, similar to that of idiocy, 

 but of less degree. 



Imbibe (im-bib') [imbibere, to drink in]. To drink or 

 suck in. 



Imbibition {im-bib -ish' -uri) [imbibitio, a drinking in]. 

 The sucking up, or capillary absorption, of moisture, 

 liquids, or gaseous substances by inorganic, or by 

 dead or torpid organic bodies. 



Imbowelling [im-bow'-el-ing). Same as Eviscer- 

 ation. 



Imbricate (im'-brik-dt) [imbricare, to cover with tiles]. 

 Applied to that arrangement of scales, feathers, leaves, 

 or floral organs in the bud, in which they overlap like 

 shingles on a roof. 



Imbricated {im'-brik-a-ted) [imbrex, a roof-tile]. Dis- 

 tinguished by overlapping. Applied to the position 

 and arrangement of scales in certain squamous diseases 

 of the skin. 



Imitation (im-it-a' -shun) [imilari, to imitate]. A 

 production that is similar to, or a copy of, another ob- 

 ject or process. I., Morbid, the occurrence of a 

 convulsive or mental affection brought about by ob- 

 serving a similar affection in another ; mental con- 

 tagion. 



Immaculate {im-ak'-u-ldt) [in, not; macula, a spot]. 

 Pure ; spotless. 



Immarginate (im-ar'-fin-at) [in, not ; marginare, to 

 furnish with a border] . In biology, having no well- 

 defined border. 



Immature {im-at-ilr') [immaturus, unripe]. Not ripe; 

 not yet of an adult age or growth. 



Immediate {im-me'-de-dt) [in, not; medio, the middle]. 

 Direct. Without anything intervening, as immediate 

 auscultation or percussion. I. Contagion, that from a 

 direct source. I. Ligature. See Ligature. I.Union, 

 union by first intention, or without suppurative granu- 

 lation. 



Immedicable (im-med' '-ik-ab-l) [in, not ; medicare, to 

 cure]. That which does not yield to medicine or 

 treatment. Incurable. 



Immersion (im-mer' -shun) [in, in ; mergere, to dip]. 

 The plunging of a body into a liquid. In medicine, 

 treatment by a continued bath. See Oil-immersion, 

 Water-immersion. I. -bath, the liquid employed tor 

 immersion. I. -battery, a form of battery in which, 

 by inclining the cell, the elements are immersed in 

 the liquid. I., Homogeneous, a fluid between the 

 objective of a microscope and the cover-glass, having 

 about the same refractive and dispersive power as the 

 glass. I., Objective, a microscope-objective, usually 

 of high power, the lower lens of which is imm 

 in a drop of water, glycerin, or oil, placed on the 

 cover-glass of the object under examination. 



Immissio (im-ish' -e-o) [L.]. Insertion. I. catheteris. 

 See Catheteiism. I. penis, introduction of the penis 

 into the vagina. 



Immission {im-mish' '-un) [immissio, a letting in]. | 

 Introduction, as of a catheter. 



Immobilization [im-mob-il-iz-a' -shun) [immobilis, ini 

 movable; facere, to make]. The surgical fixation of 

 a part (as a fractured bone) by means that prevent 

 any local motion. 



Immortality (im-mor-tal'-it-e) [immortalitas, undying- 

 ness]. Exemption from death ; unending exist 

 I. of Germ-cells. See Heredity; also, Germ-pl 



Immune {im-miin') [immunis, safe], i. Sate from at 

 tack; protected by vaccination, or some anal 

 procedure, or by previous illness. 2. A person who is 

 protected against any special virus. I. Animal. .*■ 

 Control-experiment. 



Immunity [im-mfin'-it-e) [initnunitas, exemption]; 

 condition of an organ, or of the body, whereby it n 

 the development of infectious or morbid ] 

 The inoculation of attenuated virus and of ch 

 compounds arc examples of methods by which in 

 munity is acquired. It has also been shown that inflam- 



