THE PNEUMOCOCCUS, PNEUMONIA, ETC. 51 



Sputum. — The examination of sputum may be made in order to 

 make a diagnosis as to the presence or absence of pneumonia, in 

 a case in which the physical signs are indeterminate, or to 

 establish the nature of a lobular pneumonia. 



The patient must wash out his mouth with water, which should 

 have been boiled and allowed to cool. He must then spit into a 

 clean wide-mouthed bottle, also containing boiled water, and care 

 must be taken that the sputum used for the examination comes 

 directly from the lungs, and is not merely mucus which has 

 collected in the mouth. 



The mass of mucus forming a single " spit" is agitated gently 

 in the water to remove contaminations from the bronchial tubes 

 and mouth ; the water is poured off and more added, and the 

 process repeated several times. Then the mass of mucus is fished 

 out, placed in a watch-glass, carefully opened with a pair of scissors, 

 and a piece about as big as a pea is removed from the centre of 

 the mass with a platinum loop. It is placed on a clean slide, 

 another slide pressed upon it, and the two are slid apart. The 

 films thus obtained are allowed to dry, and fixed by heat in the 

 usual way. 



One is then stained by Gram's method, and counterstained by 

 dilute carbol fuchsin for about a quarter of a minute, washed, 

 dried, and mounted, and the other with undiluted carbol fuchsin. 



The pneumococcus is a diplococcus — i.e., the individual cocci 

 are arranged in pairs. Each coccus has usually an oval or lancet 

 shape, the sharp ends of the two germs pointing away from one 

 another (Plate I., Fig. 3, and Plate III., Fig. 4). Abnormal 

 forms (round cocci, short bacilli, etc.) are frequent. The pneumo- 

 coccus has a capsule when it occurs in the living body or in patho- 

 logical exudates, but not in most cultures. This capsule does not 

 stain readily, and appears in a properly-stained specimen as a 

 clear halo round the two cocci. 



Examine your Gram specimen first. The pneumococci (which 

 will be almost black) should be clearly seen, and you should be able 

 to make out their shape and characteristic arrangement in pairs. 



The general surface of the film is stained pink, while there is a 

 clear and colourless zone round each pair of cocci. This is the 

 capsule, which is rendered distinct by "negative staining," and 

 these appearances will be better seen in a somewhat thick and 

 deeply-stained film, though if the carbol fuchsin has been allowed 

 to act too long the capsule may be stained a faint pink. There 



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