EXAMINATION OF MATERIAL FROM PATIENTS 



179 



with sterile two per cent ammonium oxalate solution in test tubes, by 

 which means the clotting is prevented, and transfers can be made more 

 leisurely to culture media. While this method is convenient in cases 

 where blood must be taken at some distance from the laboratory, it is 



FIG. 54. BLOOD-CULTURE PLATE SHOWING STREPTOCOCCUS COLONIES. 

 halo of hemolysis about each colony. 



Note 



preferable, whenever possible, to make cultures from the blood im- 

 mediately at the bedside. 



The choice of culture media for blood cultures should, to a certain 

 extent, be adapted" to each individual case. For routine work, it is best 

 to employ glucose-meat-infusion agar and glucose-meat-infusion broth. 

 At least six glucose-agar tubes should be melted and immersed in water 

 at 45 C. Before the blood is mixed with the medium, the agar should be 



