The More Easily Observed Pathological Changes in the Cerebro-Spinal Fluid, and Their Clinical Interpretations

in which simple examination of the cerebrospinal fluid, without the assistance of a laboratory or expensive apparatus, when combined with the clinical findings, can prove of the greatest value in diagnosis. It is well established that unadulterated cerebrospinal fluid is perfectly transparent, even when viewed by the strongest illumination, and although in certain cases there may be no opacity, this opacity when seen is a definite indication that disease is present. In order to determine this, some care must be taken in collecting the fluid. It is best to have at hand three tubes when withdrawing fluid by lumbar puncture. One of these tubes is specially cleaned before being sterilised, first being washed in hot soda solution, to remove all grease, and then cleaned in three washes of spirit. Into the first of these tubes the first specimen of fluid withdrawn is collected; this is usually blood-stained from injury to the anterior plexus of veins. When the flow of blood has ceased, the second tube is opened, and a few c.c. of fluid collected therein. This serves a double purpose, for by this means the needle is washed out of any remaining blood, and this specimen?although not pure enough for cytological examination?is sufficiently pure for the Wasserman reaction if needed. The third tube, which has been specially cleaned, serves to