MICKOSCOPY. 460 MICROSCOPY. if the tubercle baiilhis is to be lookeil for. Photographs of typical bacteria as seen through the microscope are shown in the article Dl.sEAfSE, Germ Tiieoky of. Epithelial cells from various parts of the respiratory tract are often present. Their origin can frequently be determined by their appear- ance. Red blood cells occur in the sputum in acute bronchitis, pneumonia, tuberculosis, and in any condition which is associated by hemorrhage into the respiratory tract. White blood" cells are also readily recognized in methylene blue stained specimens by their irregu- lar or multiple nuclei and their unstained cell bodies. They are found in acute and chronic bronchitis, in pneumonia, tuberculosis, abscess, and gangrene of the lung, in fact in any intlani- matol-y condition of the respiratory tract which is marked by a catarrhal <ir supiiurative exuda- tion. JIucus, fat droplets, fibrin, elastic fibres, crys- tals of calcium carbonate, of triple phosphates, of cholesterin. of the fatty acids, and the so- called Charcot-I.eyden crystals may be found in sputum on microscopical examination. method. For the appearance of certain gerraa see Disease, Geem Theory of. ■ Tlie 'ray' lungus. or linigus of actinomycosis of the lung, is sometimes demonstrable in the spu- tum, as are also yeasts, molds, and leptothrix. Microscopical examination of specimens from the stomach is often of value in determining the condition of that (irgan. ilatcrial is obtained as. MOLD PLANTS X 100. vomitus or by introducing the stomach tube. In- completely digested food may be recognized as muscle fi"bres, fibrous and elastic fibres, fat, starch, and various kinds of vegetable cells. Epithelial cells from the mouth or uesophagus or from the stomach itself nuiy l)e found. Red blood cells may come from the stomach or may have been swallowed. White blood cells are quite conmionly fovmd. When in large numbers they indicate "suppurative inflammation. The condi- tion of the stomach may sometimes be deterniincci VEAST X 250. A large number of harmless species of bacteria are found in si)utum, most of these being derived from the mouth, nose, and upper respiratory tract. Of disease-producing species the most im- portant are the tuliercle l)acillus, the bacillus of inlluenza, the pneumo-bacillus of Friedliinder, the pneumococcus, the streptococcus, and the staphy- lococcus. (For the staining ipialitics and appear- ance of the tubercle bacillus, see article on TinERCiLO.sis.) The bacillus of inlluenza is an cxtremclj- minute bacillus measuring only about half the" length of the tul)ercle bacillus. It is apt to occur in clumps and does not stain very readily with methylene blue. A rather weak aidution of carbol-'fuchsin, however, gives good staining of the micro-organism. The bacillus of Friedliinder is the less conunon of the pneiunonic organisms. It is capsulatcd and decolorizes by Gram's nietho<l of staining. The more com- mon cause of pneumonia, the pneumocwcus or diplococcis lanceolatus. is also surrounded by a capsule, but is shorter than the Friedliinder bacillus and does not decolorize by Gram's rrp cKLtH. (fl) noturnl condition: (b) otter the addttton of acetic add. bv the forms of microorganism which are found growing there. Thus a long bacillus which oc- curs in chains, the so-called 15oas-Gppler bacillus, is a conunon habitat of a stomach which is free from hyilrochloric acid, and whose contents are undergoing lactic acid fermentation. The Sar- cina', on the other hand, a species of cocci which
