300 PRECIPITINS 



actions, to prepare controls with known normal and luetic serums and 

 with distilled water. 



None of these reactions has been found specific, and none has been 

 generally adopted, the far greater accuracy of the Wassermann reaction 

 having made this method more valuable. 



Noguchi Butyric-acid Test. Noguchi has devised a very useful 

 test for the detection of an increased amount of protein, particularly 

 globulin, in cerebrospinal and other body-fluids. In my experience this 

 test has proved of particular value in establishing the differential diag- 

 nosis between serous and tuberculous meningitis, being negative in the 

 former and positive in the latter, whereas in both the fluid may be clear, 

 the cytology may be indefinite, and tubercle bacilli may escape detection. 

 Serous meningitis is not a true infection, but a reflex vasomotor disturb- 

 ance of the cerebral vessels, causing an outpouring of serum that leads 

 to various pressure symptoms closely resembling those of a true meningi- 

 tis. This condition is particularly common during childhood, and the 

 general symptoms, the increased pressure of the cerebrospinal fluid, and 

 its clear, watery character, are features that resemble those of tubercu- 

 lous meningitis. It is just in such cases and they are frequent that 

 I have found this protein reaction of considerable value. A positive 

 reaction practically always means a true meningitis; a negative reaction 

 usually means "serous meningitis," with a much better prognosis if the 

 underlying cause is corrected. 



Noguchi has found the test positive in about 90 per cent, of cases of 

 general paralysis and in 60 per cent, of cases of locomotor ataxia or cere- 

 bral or spinal syphilis. In the diagnosis of syphilis the Wassermann 

 reaction with cerebrospinal fluid has greater value than the protein re- 

 action. However, the best results in diagnosis are usually secured by a 

 Wassermann test, butyric-acid test, and total and differential cell-counts. 

 In a case where the diagnosis rests between tuberculous meningitis and 

 syphilis, a positive butyric-acid test and a negative Wassermann reaction 

 would decide in favor of the former. 



The test is extremely simple. Into a small, thin-walled test-tube 

 place 0.2 c.c. of cerebrospinal fluid (which must be clear and free from 

 blood) ; add 1 c.c. of a 10 per cent, solution of butyric acid in nornial salt 

 solution; heat over a low flame and boil for a short period. Then add 

 quickly 0.2 c.c. of a normal solution of sodium hydroxid and boil once 

 more for a few seconds. The presence of an increased content of protein 

 is indicated by the appearance of a granular or flocculent precipitate, 



