l8o BACTERIOLOGICAL DIAGNOSIS. 



A great advantage of this method is that it does away 

 with the necessity for any elaborate process for the 

 sterilisation of the skin. The authors quoted above 

 found that the results which they obtained were as good 

 after simple cleansing of the skin with soap and water 

 as after the use of antiseptic dressing. Nor is this to 

 be wondered at when we think of the very small chance 

 of any bacteria being carried through the skin and 

 subcutaneous tissues into a vein by a very fine and 

 sharp needle. 



The advisability of employing some such method in 

 which the blood is drawn directly from a vein in place 

 of the simple skin puncture is very apparent from the 

 researches of Kiihnau (" Zeitschft. f. Hyg. and Infct.," 

 1890), who made parallel series of experiments by the 

 two methods. He found that in cases in which the 

 blood drawn directly from the vein remained sterile, 

 growth (mostly streptococci or staphylococci) occurred 

 in as many as ninety per cent, of cultures inoculated 

 from skin punctures though the most careful antiseptic 

 precautions were used. 



EXAMINATION OF BLOOD BY CULTURAL 

 METHOD. 



This is a matter which is best carried out in a proper 

 laboratory by an expert. If the practitioner attempts 

 to carry it out for himself his best plan is to make a 

 series of inoculations on the surface of agar. :|: The tubes 



* The ideal method is to make the inoculation directly into a large 

 quantity of broth and to make sub-cultures on agar later. This 

 method has the advantage that the blood becomes largely diluted, 

 so that any bactericidal substances which it may contain are less. 

 likely to injure the bacteria. It is, however, rather more difficult. 



