The material of this paper is arranged in the following order :
Negative reactions with testicular substrate and male dementia praecox serum.
A comparison between the blood-serum of normal persons and those suffering with general paralysis of the insane as regards proteolytic action on brain substrates at various stages of washing.
Proteolysis of substances precipitated from the water used for washing various organs in the course of preparing substrates.
Comparison of the proteolysis of emulsions, prepared by concentrating the washings from brain substrate, by serum from general paralysis and normal persons.
In a previous communication1 we proved, first, that the serums of normal animals contain ferments capable of giving positive Abderhalden reactions with substrates prepared from many body tissues, and second, that the substance (or substances) which gives the reaction may be removed from the substrates if the washing2 with acidified water