134 CLINICAL BACTERIOLOGY AND HiEMATOLOGY 



[There are also characteristic chemical changes in uraemia, to 

 which I have paid a good deal of attention of late. In health the 

 cerebro-spinal fluid contains about 0*035 to 0*04 per cent, of urea, 

 0-7 per cent, of chlorides, and has a freezing-point of — o'55° C, or 

 thereabouts. In renal disease in which the kidneys are acting 

 well these figures are but slightly disturbed, but in uraemia there 

 is abundant evidence of retention of soluble substances. The urea 

 increases greatly — the maximum I have seen being 0-4 per cent. — 

 the chlorides may rise to i per cent., and the freezing-point is 

 depressed. I believe this to be the simplest test of the functional 

 capacity of the kidney, the chemical examinations being easy in a 

 substance of such simple constitution as the cerebro-spinal fluid. 

 It is occasionally of value in patients found unconscious. In 

 one such case I was able to exclude uraemia definitely, though 

 the urine contained albumin and casts : it turned out to be a case 

 of poisoning. In uraemia there is often the additional advantage 

 of its affording a relief to some of the symptoms. Further details 

 are outside the scope of this work.] 



(d) Bacteriological. — The chief organisms which cause acute 

 meningitis are given in the following table, which is modified 

 from one given by Osier : 



Primary {i.e., not dependent on an obvious lesion elsewhere in the body). 



1. Cerebro-spinal fever — 



,,,'., . yWeichselbaum's diplococcus, or meningococcus. 

 {bj. EpidemicJ 



2. Pneumococcic — 



(a) Pneumococcic infection of meninges alone, not de- 



pendent on disease of distant parts of the body. 



(b) Pneumococcic infection of meninges occurring as IPneumococcus. 



part of a general septicaemia without obvious 

 primary lesion. 



Secondary. 



A. To direct extension from local disease of the cranium, middle ear, fossae, 



spinal column, etc. 

 Pneumococcus. 

 Staphylococci. 

 Streptococci, etc. 



B. To septicemic infection due to disease in a distant part of the body. 



(a) Pneumococcic — 



Secondary to pneumonia, endocarditis, etc. 

 Pneumococcus. 



