(d) Sections are carried on glass or platinum needle into a dish of Pappenheim’s pyronin-methyl green stain and kept in a water bath at 40° C. five to seven minutes.
(e) Quickly cool dish in running water.
(f) Wash off superfluous stain in plain water.
(g) Absolute alcohol to differentiate—until no more stain comes away from section.
(h) Clear in Bergamot oil.
(i) Mount in balsam.
The normal cell count may be stated as being up to 6 cells per cmm.; from 6 to 12 cells may be considered as suggestive of pathological condition and more than 12 cells per cmm. as definitely pathological. The type of cell in syphilitic diseases is preponderantly the small lymphocyte. A low percentage, that is, very rarely over 20%, of large lymphocytes, endothelial phagocytic cells, polymorphonuclear leucocytes and plasma cells may also be found. The finding of plasma cells in any number in the spinal fluid is suggestive although not conclusive evidence for the diagnosis of paretic neurosyphilis.
Globulin is an albumin which is precipitated by half saturation with a salt. A very simple and satisfactory test is known as the Nonne-Appelt test, which has been modified by Ross-Jones. Into a test tube of small diameter, run 1 cc. of spinal fluid. Place under this fluid with a pipette, 1 cc. of a saturated solution of ammonium sulphate ((NH4)2SO4). If any globulin is present a white, sharply-defined ring will form at the junction of the two fluids. According to our readings, a ring that is just visible with the aid of a black background is called 1+, a ring that is just visible without the black background, 2+; a ring easily perceptible, 3+ and a relatively very heavy ring, 4+. On shaking the tube, if globulin is present, the fluid will show turbescence.
Another simple globulin test used in our laboratory as a check on the Nonne-Appelt test is the Pandy test. A few cc. of a clarified 10% solution of phenol are placed in a watch glass. One drop of spinal fluid is run into this solution. A milky turbescence indicates globulin.
The presence of globulin in the spinal fluid is always an indication of abnormality of the cerebrospinal axis. There is nothing differential in this finding as it occurs in all inflammatory processes. However, it is characteristically present in most cases of neurosyphilis (exception to the rule: the pure vascular type does not show globulin in a very high per cent).