The investigation of which this paper gives a brief summary relates to serum-albumin rather than to serum-globulin, and the experiments may be arranged in two categories: first, those relating to heat-coagulation; and secondly, those relating to the action of certain salts upon the proteids of blood-serum. The apparatus used for the determination of the temperature of the heat-coagulation of proteids was not that which has been usually employed for the purpose, and which consists of two beakers containing water, one within the other, and heated gradually over a sand-bath; the substance under investigation being placed in a test-tube contained within the inner beaker. The chief objection to that method is that the rise of temperature in the water in the beakers takes place with extreme slowness, so that changes are apt to occur in the proteid during the experiment. To meet this difficulty an apparatus was devised by Professor Schäfer, which was found to be I extremely easy to use, and of which the great advantage consists in f the readiness with which a constant temperature is maintained for a s considerable time. It may be briefly described thus: the liquid of which one wishes to determine the temperature of coagulation is placed in a test-tube in sufficient quantity to cover the bulb of a thermometer put into it; the test-tube is placed in the neck of a flask containing water; this water is kept at the desired temperature by the following means. It is in the first place kept constantly running, entering by one tube and leaving the flask by another tube inserted as a T-piece in the upper part of the neck. The water is warmed by passing it through a coil of tubing contained in a vessel in which water is kept constantly boiling. By regulating the rate at which the water flows through this apparatus the desired temperature is maintained.
III. The proteids of serum
