The theory of hæmoclasia, which was first propounded by Widal, rests on the assumption that, during the digestion of proteins, a leucocytosis normally occurs in the blood. When the liver is diseased, proteose substances find their way into the systemic circulation, and produce a series of manifestations characterized by lowering of the blood-pressure, hypercoagulability, leucopenia, decreased refractive index of the blood and fewer blood-platelets. From this discovery a clinical test was evolved, which was at one time believed to be of considerable assistance in estimating the functional efficiency of the liver. In the performance of this test the number of white blood-corpuscles in the circulation is alone taken as a criterion of the presence or absence of hæmoclasia, the other phenomena, e.g., raised blood-pressure, hypercoagulability, etc., not being usually investigated. A white blood-count is performed on a fasting patient, who is then given 200 grm. of milk. Further leucocytic estimations are thereafter made at intervals of twenty and forty minutes, and if a leucocytosis fails to appear, or a leucopenia occurs, the patient is said to exhibit an hæmoclastic crisis.