THE PLEURA 123 



body, describing the methods to be employed in the investigation 

 of the inflammatory exudates which they may contain, and the infer- 

 ences which may be drawn from the results of the examination. 



THE PLEURA 



There is but little to be said about the method to be employed 

 in the collection of fluid from the pleural cavities. The most 

 careful antiseptic precautions are to be taken, and the region to be 

 punctured should be decided by consideration of the physical signs. 



The examination of the fluid thus obtained may be either 

 microscopical, cultural, or by injections into animals. If the 

 latter are required (and inoculation should be performed in all 

 cases where a tuberculous origin is suspected) a considerable 

 quantity of the fluid — an ounce or more — should be enclosed in 

 a bottle which has been sterilized by boiling, and forwarded at 

 once. A drachm or more of lo per cent, sodium citrate solution 

 (boiled) should be added to prevent coagulation. 



Where the diagnosis is to be made by cultural methods, and 

 the cultures are not to be made on the spot, the fluid is best 

 stored or sent to a laboratory in pipettes. These are to be filled 

 from the syringe direct ; the needle is to be removed, and the end 

 of the pipette (sterilized by being passed through the flame) is 

 passed into the fluid, and filled by gentle suction at the other end. 

 Each end is then sealed in a flame, care being taken not to heat 

 the fluid. Two or three such tubes should be sent. 



Clear fluid from the chest rarely shows any micro-organisms on 

 microscopical examination. Cultures are usually sterile ; where 

 streptococci or pneumococci are found the inflammation is likely 

 to pass on into suppuration. The great majority of these cases 

 of "simple " acute pleurisy are really due to the tubercle bacillus, 

 but their true nature is difficult to determine except by inoculation 

 experiments. A cytological examination of the fluid should be 

 made, and in tuberculous cases the cells present will usually be 

 found to be lymphocytes, with an occasional admixture of blood- 

 corpuscles (see p. 237). If the fluid does not clot spontaneously, it 

 may be very thoroughly centrifugalized, and films prepared from 

 the deposit and stained for tubercle bacilli in the ordinary way ; 

 but they are not always found even in true cases of tuberculous 

 pleurisy. Where the fluid coagulates spontaneously, the best 

 plan is to allow the clot to retract until it has shrunk to a small 



