1 86 CLINICAL BACTERIOLOGY AND H/EMATOLOGY 



THE BACTERIOLOGICAL EXAMINATION OF 

 THE BLOOD 



The bacteriological examination of the blood is not so im- 

 portant as might be thought, as it is only in comparatively few 

 diseases that pathogenic bacteria are present in the circulation 

 in such quantities as to render the search for them in the 

 relatively small amounts which are withdrawn for examina- 

 tion at all promising. The method is becoming- of more im- 

 portance daily, since promising results have been obtained in 

 the treatment of septicaemic diseases by means of specific vac- 

 cines, which, to get the full advantage of the process, should 

 be obtained from cultures of the patient's own bacteria. 



The chief organisms which have been found in the blood 

 are : 



i and 2. Streptococci and Staphylo cocci. These are found 

 in cases of septicaemia, pyaemia, ulcerative endocarditis, etc.; 

 they indicate an extremely bad prognosis, though the use of 

 vaccines has now improved matters somewhat in this respect. 

 The chief importance which attaches to the discovery of these 

 organisms is that it absolutely settles the diagnosis (always 

 provided that there are no errors in technique), and that it in- 

 dicates whether the use of a vaccine or antistreptococcic 

 serum is advisable or not; the serum is useless in cases of 

 septicaemia, etc., which are not due to streptococci. 



A word of warning is necessary in the interpretation of 

 results which indicate that staphylococci are present in the 

 blood. These organisms are constantly present in the skin, 

 and may be found in cultures, unless rigid antiseptic precau- 

 tions are taken. Streptococci may also occur as contamina- 

 tions of cultures, but comparatively rarely. 



3. Anthrax Bacilli. These may be detected with ease and 

 certainty, but they are probably never found in the blood until 

 it is too late to save the patient. 



4. Tubercle Bacilli. These are only present in very scanty 

 numbers, and are very difficult to detect. The diagnosis of 

 miliary tuberculosis is to be made by other methods, chiefly 

 by that of exclusion. 



5. The pneumococcus is found in severe cases of pneumonia 

 (it might be found in most cases if a sufficiently large quan- 



