1/2 CLINICAL BACTERIOLOGY AND H^MATOLOGY 



dead, and this makes the prognosis better. The prognosis is 

 also good in cases in which very few cocci are present, and 

 in those in which the cocci that are present are largely con- 

 tained in the leucocytes; in this case they may lose their 

 power of retaining Gram's stain. 



The streptococcus is also readily demonstrated by a simple 

 microscopical examination; it grows readily on agar, forming 

 small round colonies, which do not tend to coalesce and are 

 more opaque in the centre than at the periphery. 



The pus is not generally very thick, and has a yellow colour. 

 It separates into two layers, the upper transparent layer being- 

 much more abundant than is the case with pnettmococcic pus. 



This form of empyema is rare in children, but is perhaps, 

 on the whole, the commonest one in adults. The prognosis 

 is much worse than in the pneumococcic cases, and thorough 

 drainage and resection of the ribs is essential. 



Staphylococcic empyemata, according to Netter, are very 

 rare; the single case in which he found the staphylococcus 

 alone was secondary to ulcerative endocarditis. He also 

 states that when this organism is found in the pus tubercle 

 bacilli are often present as well. The prognosis of these 

 cases, therefore, appears to be bad. 



The tubercle bacillus is responsible for a comparatively 

 small number of cases, and the results of operative interfer- 

 ence are not gratifying. The prognosis is worse than in any 

 other form of the disease. 



The pus is usually white in colour, and thin and watery. 

 It may contain small masses of white caseous material. The 

 leucocytes which it contains are nearly all lymphocytes, unless 

 a secondary infection with pus organisms has taken place. 



The diagnosis may be made from a careful microscopical 

 examination, but to this end it must be careful, as the bacilli 

 are often present in but scanty numbers. 



Actinomycosis is a comparatively rare cause. The pus 

 usually shows the characteristic granules, and the organism 

 is easily found microscopically. 



If no organisms are found after a thorough microscopical 

 examination, the inference is that the, case is tuberculous. If 

 a cultural examination is also negative the inference becomes 

 almost a certainty. 



The empyemata arising from rupture of the oesophagus, 



