A Laboratory Hand book of Urine Analysis And Physiological Chemistry

a protein substance present in the nitrate ? Treat the precipitate on the filter with cold water. Test the filtrate with acetic acid and heat. Note the ready solubility of the precipitate in water. Prepare a similar tube, saturating the solution with crystalline magnesium sulfate. Heat at 35 C. for the same length of time. Note the formation of a very slight precipitate of egg-globulin con-, tained in the egg-albumin. Magnesium sulfate precipitates globulins, but does not precipitate albumins. Filter the solution, and apply the acetic acid and heat test. Note the copious precipitate of albumin which has not been precipitated by the magnesium sulfate. THE BLOOD. The blood as existing in the body may be classified into arterial and venous. These two kinds are distinguished by their content of oxygen and of carbon dioxid. They are also distinguished by their color, which is due to the blood-pigment being in different stages of oxidation. In arterial blood the pigment consists for the most part of oxyhemoglobin, characterized when in sufficient quantity by its bright-red color and its spectrum. Venous blood has a darker hue, and the pigment has lost a part of the loosely combined oxygen present in oxyhemoglobin and has been converted into hemoglobin. This also has a characteristic spectrum. The blood consists, roughly, of two parts, the corpuscles, or organized elements of the blood, and the plasma, in which the corpuscles float. An average of human blo...