62 BACTERIOLOGICAL DIAGNOSIS. 



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 stained in dilute carbol-fuchsin for about two 

 minutes and then washed very thoroughly in water. 

 The other is stained by Gram's method. 



The pneumococcus is a diplococcus, i.e. 9 the indi- 

 vidual 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). Abnormal forms (round cocci, short bacilli, &c.) 

 are frequent. The pneumococcus has a capsule when it 

 occurs in the living body or in pathological 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 pneumo- 

 cocci should be clearly seen, and you should be able to 

 make out their shape and characteristic arrangement in 



