Page:The New International Encyclopædia 1st ed. v. 13.djvu/506

* MICKOSCOPICAL SOCIETY. 456 MICROSCOPY. a membership of three hundred, and an extensive collection of specimens and exliihits at Pittsburg, Pa. Its ol)jects are the encouragement of micro- scopical research, and the diffusion of knowledge on the subject of microscopy. MICROSCOPY. CuNicAL. With the rapid in- crease made in comparatively recent times in the perf<'(ti(in of instriments at our disposal and in our knowledge of the differences in normal and pathological appearances of body tissues and organs and their products, the micrnsco]ie has come to be an indispensable adjunct to medical diagnosis. (See the article Mrro.scope for de- scription and illustration of microscopes.) For most diagnostic work two objectives are sulUcient, a low power having a focal length of about two- thirds of an inch, and a high power having a focal length of abovit one-tiftb of an inch. For a microscopic examination of l)acteria and the blood a higher magnification is in many cases desirable. Before examining with the microscope most specimens require some special preparation. As these preparations differ for different siiecimens, they will be described vinder separate headings. Urine. Microscopic examination of the urine is made for the purpose of determining disease or as rough spherical crystals. (c) Hippuric acid crystals are rather infrequently found in acid urine. (d) Phosphates, ammonium-mag- nesium or 'triple phosphate' crystals occur in slightly acid and in alkaline urine. They are CRYSTALS OF C.VLCIUM PH08PHATK X 150. of the kidney, ureter, bladder, urethra, etc. For microscopic examination the specimen of nrine should be allowed to stand for from eight to twelve hours and the part examined taken l)y means of a pipette from the bottom of the fluid, or the urinary solids nuiy be tlirown down liy means of a centrifugal machine <-alled the centri- fuge. A snuill dr<q) of the urine is ]ilaced upon a glass slide and covered by a thin piece of glass known as a cover glass. The specimen may then be examined. Crystalline Si'bstances. (a) Uric acid oc- curs as 'whet-stone' shaped crystals. These lying across one another in groups form radiating masses or rosettes. Crystals somewhat dumb- bell in shape are less eonuiion. and after the addition of acid to urine large jilate-like crystals of uric acid may be found, (b) The salts of uric acid or urates may also be seen under the niicroscojie. usually as a granular deposit, 'amor- phous urates.' In urine which is undergoing ammoniacal fermentation, anmionium urate crys- tals occur either as clumps of short thick needles CBVSTALB OF CALCICM OXALATE X 350. large and are usually described as 'coffin-lid' in shape. In alkaline urine the phosphates some- times come down as fine feathery 'snow-flake" crystals. Calcium phosphate occurs as clear, slender, needle-shaped crj'stals. Large colorless plate-like crystals of basic magnesium phosphate and granular deposits of the basic phosphates of lime and magnesium may also be found in alka- line urine, (e) Calcium oxalate crystals occur in acid urine. They are clear and diamond or 'envelope' shaped. Less coiiunon are crystals of a somewhat dumb-bell sliape. (f) Calcium car- bonate is found in alkaline urine which is under- going fermentation. It occurs as coarse granules which dissolve with gas formation on the addi- tion of acetic acid, (g) Less common crystals found in urinary sediments arc those of biliru- bin, hiematoidin, leucin, tyrosin, and cystin. ® ® © ^ ® „© (Si ® © 00 a. EPITHKLIAL CELLS. (.1) Uound; (*) columnar; (r) sqimmous. Organic Substances. (a) Epithelial cells ULiinly from the bladder and vagina occur in normal urine. In inllammatory conditions of the bladder and vagina their numlier is greatly in- creased. Epithelium from the kidney may also occur in the urine. II is cuboidal or ecilumnar in shape and most abundant in degenerative condi- tions of the kidney, and in diseasi> of the kidney pelvis. Pigmented columnar epithelium from the seminal vesicles may sometimes be foimd. (I)) Casts are among the most important of the or- ganic substances found in iirine. indicating as they often do serious conditions in the kidneys. They are formed by the coagulation of albu- minoid matter in the tubules of the kidney, thus