_Cryoscopy of Blood._--In order to determine the osmotic pressure of the blood at 37deg C., _i.e._ 98.6deg F., the normal temperature, we proceed as follows. On freezing the blood, we find that it congeals at -.56deg. Its molecular concentration is therefore .56 / 1.85 = .30, or about one-third of a gramme-molecule per litre. Its osmotic pressure at 0deg C. is therefore .3 x 22.35 = 6.7 atmospheres. The increase of pressure with temperature is the same as for a gas, viz. 1/273, or .00367 of its pressure at 0deg for every degree rise of temperature. The increase of pressure at 37deg is therefore .00367 x 37 x 6.7 = .9 atmospheres. The total osmotic pressure at 37deg is therefore 6.7 + .9 = 7.6 atmospheres. _Rise of Boiling Point._--Water under atmospheric pressure boils at a temperature of 100deg C. The addition of a solute whose solution does not conduct electricity, such as sugar, causes a rise in the boiling point proportional to the molecular concentration of that solute. _Lowering of the Vapour Tension._--The vapour tension of a liquid is lowered by the addition of a solute. A liquid boils at the temperature at which its vapour tension equals that of the atmosphere. Since an aqueous solution of sugar at atmospheric pressure does not begin to boil at 100deg C., it is manifest that its vapour tension is then less than that of the {21} atmosphere. The addition of a solute such as sugar, whose solution is not ionizable, and therefore does not conduct electricity, lowers the vapour tension of the solution in proportion to the molecular concentration of the solute. _Corresponding Values._--We have thus found five properties of a solution which vary proportionally, so that from the measurement of any one of them we can determine the corresponding values of all the others. These are-- 1. The Molecular Concentration. 2. The Osmotic Pressure. 3. The Diminution of Vapour Tension. 4. The Raising of the Boiling Point. 5. The Lowering of the Freezing Point.