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.¢., 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 
