EFFECTS OF ATMOSPHERIC PRESSURE. 251 



(e) Crystals of various kinds : Fatty-acid crystals (a) , arranged in bundles of 

 fine needles, usually lying in whitish, cheesy, fetid lumps of sputum. They indi- 

 cate a more profound process of decomposition affecting the stagnating secretion 

 and the underlying tissue. Crystals of leucin and tyrosin are rarely found as 

 decomposition-products of the albuminates. Tyrosin is found more abundantly 

 after rupture of an old abscess into the lungs. Colorless, octahedral or rhombic 

 platelets with elongated points Charcot's crystals (c) have been found in the 

 expectoration in cases of asthma, hang in and on peculiar, spirally wound plugs 

 of exudate from the narrow air-passages; they have also been found in connection 

 with other exudative affections of the bronchi. These structures, also called 

 Curschmann's spirals, are produced when the respiratory air, in passing by, draws 

 out parts of the secretion into threads, and rolls them spirally to and fro. Hema- 

 toidin-crystals (6), from old effusions of blood in the lungs, occur rarely; likewise 

 cholesterin-crystals (d) , arising from broken-up collections of pus. 



(/) Fungi and other low organisms are found in the sputum, being taken in 

 during inspiration. The threads of leptothrix buccalis (12) occur frequently, 

 having been detached from deposits on the teeth. Mycelial threads and spores are 

 found in the sputum in cases of thrush, which occurs frequently in the mouths 

 of nursing infants as white, spreading deposits (oidium albicans). Among the 

 bacteria, the mucous-membrane streptococci (mostly diplococci) are constantly 

 found, and frequently the micrococcus albus liquefaciens and harmless saprophytes; 

 pyogenic cocci usually occur only in cases of pulmonary tuberculosis. In the 

 presence of gangrene of the lungs monads and cercomonads have been found, in 

 cases of pneumonia at times the bacillus pneumonias of Friedlander, in cases of 

 influenza the influenza-bacillus of Pfeiffer and Canon, in cases of whooping-cough a 

 minute diplococcus (according to Czaplewski and Hensel a non-motile bacillus), 

 in cases of mumps a bacterium similar to the gonococcus, in cases of measles the 

 bacillus causing that disease, in cases of pulmonary tuberculosis without exception 

 the tubercle-bacillus. Rarely the sarcina is found; this is encountered more fre- 

 quently in the stomach in the presence of gastric catarrh, and also in the urine. 



With regard to its external appearance sputum may be described as mucous, 

 muco-purulent, or purulent. When heated at 60 C. all sputa are reduced to a 

 uniform degree of fluidity. 



The sputum may have an abnormal coloration. Thus, it may be red from 

 blood-pigment; if it remains long in the lungs, the blood-pigment may run through 

 a whole scale of colors (as in external, visible blood-tumors), and it may thus give 

 the sputa a dark-red, bluish-brown, brownish-yellow, deep-yellow, yellowish-green, 

 or grass-green color. The sputum is sometimes yellow in cases of jaundice. 

 Colored dust, if accidentally inspired, may also color the expectoration. 



The odor of the sputa is usually stale, and more or less unpleasant. It be- 

 comes ill-smelling when it has remained for some time in pathological cavities in 

 the lungs; it is stinking in the presence of gangrene of the lungs. 



EFFECTS OF ATMOSPHERIC PRESSURE. 



At the normal pressure of the atmosphere, with the barometer regis- 

 tering 760 mm. of mercury, a pressure is exerted on the entire surface 

 of the body amounting to from 15,000 to 20,000 kilos, corresponding 

 to the extent of surface 103 kilos to each square decimeter. This 

 pressure acts on the body equally from all sides, and in those internal 

 air-spaces as well which are in direct communication with the outer 

 air either constantly as the respiratory tract, the sinuses of the 

 frontal, superior maxillary, and ethmoid bones or only temporarily 

 as the digestive tract and the tympanic cavity. If an air-filled space, 

 for example the tympanic cavity, be closed off from the outer air for 

 some time, a rarefaction of the gases in the space occurs, as a result of 

 the consumption of oxygen and its replacement by a smaller volume of 

 carbon dioxid. As the fluids of the body (blood, lymph, secretions, 

 parenchymatous juices) are practically incompressible, their volume 

 may be regarded as unchanged by the prevailing pressure, 

 however, absorb gases from the atmosphere in accordance with the pre- 



