Albumin Test. Albumin in small quantities is present in all spinal fluids. Increase over the normal amount occurs in pathological conditions such as most cases of neurosyphilis, especially in those in which globulin is found. Any albumin precipitant may be used for rough clinical calculation, comparing the amount of precipitate with that from the normal fluid. Our method is to place 1 cc. of spinal fluid in a small test tube of about 5 mm. diameter and to precipitate the albumin by the addition of 3 drops of 33⅓% of trichloracetic acid. This test has its chief value as confirmatory of the globulin test, since in the vast majority of instances where globulin is found there will also be found an increase in albumin.
The Gold Sol Reaction is an empirical test discovered by Carl Lange in the utilization of the work of Zsigmondi with solutions of colloidal gold and albumins. Briefly the details of the test are as follows:
Ten tubes are set up in a rack. To the first tube 1.8 cc. of a 0.4% of salt solution is added and to each of the following tubes 1 cc. of this solution. Then to the first tube containing 1.8 cc. of salt solution one adds 0.2 cc. of the spinal fluid to be tested. This gives a dilution of 1 to 10. From this tube 1 cc. is pipetted into the second tube and this process continued through the ten tubes. This gives dilutions of spinal fluid of 1 to 10, 1 to 20, 1 to 40, etc., to 1 to 5120 in the last tube. Then 5 cc. of colloidal gold solution is added to each tube. A positive reaction is indicated by the precipitation or throwing down of the colloidal gold into its metallic form. This produces a change in color. This precipitation may be partial or complete and the amount of precipitation is indicated by the color and is read as follows:
The unchanged fluid is called 0; a slight change giving a red-blue as 1; a further change giving a blue-red as 2; a straight blue as 3; a lavender or violet as 4; and the colorless fluid representing complete precipitation as 5. The numbers are placed in a row, indicating the tube in which the color occurs. The fluid from a case of paretic neurosyphilis will give a complete precipitation beginning in the first tube and running through a number of tubes and then grading off. It may be indicated 5 5 5 5 4 3 1 0 0 0. The characteristic reaction of fluids from tabetic and diffuse neurosyphilis is less strong than from the paretic. The greater part of the reaction will take place, however, in the first five tubes, but as a rule it will not begin very strongly in the first two. A characteristic reaction is 1 2 3 3 2 1 0 0 0 0. Another reaction that may be considered characteristic of the tabetic or diffuse form is 3 3 3 2 1 0 0 0 0 0. Fluids from non-syphilitic cases as a rule give a reaction having its greatest intensity beyond the fifth tube, that is, in the high dilutions.
A reaction characteristic of brain tumor or tuberculous meningitis is 0 0 0 0 1 3 3 2 1 0.
The conclusions that may be drawn from the gold sol reaction have been summarized by one of the authors as follows:
1. Fluids from cases of general paresis will give a strong and fairly characteristic reaction, especially if more than one sample is tested, in the vast majority of cases.
2. Very rarely a general paresis fluid will give a reaction weaker than the characteristic one.
3. Fluids from cases of syphilitic involvement of the central nervous system other than general paresis often give a weaker reaction than the paretic, but in a fairly high percentage of cases give the same reaction as the paretics.
4. Non-syphilitic cases may give the same reaction as the paretics; these cases are usually chronic inflammatory conditions of the central nervous system.