This communication is the record of a laboratory equipped for serological work. It does not concern itself with the post-mortem findings, nor does it attempt to discuss the clinical distinctions of the diseases scheduled. The material was obtained from the Neurological Institute and in a measure from the Manhattan State Hospital, Ward's Island. The interesting work of Plaut has shown the necessity of a more definite laboratory knowledge of tabes, general paresis and cerebrospinal lues. In the above mentioned work there is little to help one in the differentiation between difficult cases of paresis and cerebrospinal syphilis, nor do other writers shed much light on the situation from a laboratory standpoint. The material analyzed in this communication, 340 cerebrospinal fluids and as many serums, we have divided into four groups or types:
The negative types.
The positive types.
The aberrant types.
The post-therapeutic