In 1915, Emanuel1 announced a new colloidal reaction in the spinal fluid. He used gum mastic, a reagent which was very easily prepared. Of thirty tests made in psychiatric patients, there occurred complete precipitation in all the tubes in fourteen syphilitic cases (paresis, tabes and cerebrospinal syphilis). Cutting,2 using a slightly modified technic, examined the spinal fluid of 200 psychiatric patients. Only the syphilitic patients gave positive results, but the number of tubes in which complete precipitation occurred varied. Lowrey3 obtained varying degrees of precipitation in twenty different paretic fluids, as well as a few positive results in nonsyphilitic patients.
The present study was undertaken to determine whether different "curves" occurred in cerebrospinal syphilis, tabes dorsalis and paresis, but owing to the apparently irregular results, was extended to determine, if possible, the mechanism of the gum mastic reaction, as well as the examination of syphilitic and nonsyphilitic