138 CLINICAL BACTERIOLOGY AND HEMATOLOGY 



bacteria from the stained films, and predominance of lymphocytes. 

 In these cases the fluid often undergoes a very slight coagulation, 

 delicate cobweb-like threads being observable after some hours. 

 This is in itself strong evidence of tubercle, and if the delicate 

 coagulum can be withdrawn, dried on a slide, and stained by 

 Ziehl-Neelsen's method, there is a fair chance of finding bacilli 

 entangled with it. This is not very easy to do, the best method 

 being to fish it out with a very fine piece of capillary tubing no 

 thicker than a pin. It is easy enough to pick it out with a 

 platinum needle, but almost impossible to get it off the latter on 

 to the slide. 



The other varieties of meningitis do not call for special mention. 



The chief value of lumbar puncture to the surgeon is that it 

 enables him to diagnose a concomitant meningitis {indicating the 

 uselessness of an operation) in cases of lateral sinus thrombosis 

 and cerebral abscess. The fluid usually becomes bloody within 

 twenty-four hours of a fracture of the base of the skull or lacera- 

 tion of the brain. This may assist in the diagnosis of obscure 

 injuries, or of the cause of a case of unconsciousness in which no 

 history can be obtained. 



Ha;morrhage into the meninges is indicated by the withdrawal 

 of blood-stained fluid, but it must be remembered that the first few 

 drops may contain a small quantity of blood which has entered 

 the needle during its passage through the tissues, while the rest 

 is clear. Blood-stained fluid may occur in meningitis, and should 

 be submitted to a full examination for leucocytes and bacteria. 



THE BACTERIOLOGICAL EXAMINATION OF THE 



BLOOD 



The bacteriological examination of the blood is not so important 

 as might be thought, as it is only in a very few diseases that 

 pathogenic bacteria are present in the circulation in such quantities 

 as to render the search for them in the minute amounts which are 

 withdrawn for examination at all promising. The method is 

 becoming of more importance daily, since promising results have 

 been obtained in the treatment of septicsemic diseases by means 

 of specific vaccines, 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 : 



