GLOBULINS, or GLOBULIN, and GLOBULINS. Globuline, as it was spelled until recently, was considered in the earlier stages of scientific physiology the proteine princi ple of the red blood corpuscles. According to an analysis of Lehmann, it constitutes about 282 parts in 1000 of the blood globules, water constituting 638 parts, the remain der being composed of litematine, 17 parts; alkaline salts, 8 parts; with some fatty and extractive matter. This globuline is insoluble in the plasma of the blood, but is soluble in water and diluted blood. Rollet, by alternately freezing and thawing blood and repeating the operation several times, caused the hrematine to separate from the red corpuscles. By this operation the blood loses its opacity, and the decolorized globules are seen floating in the darkly colored though transparent serum. Views in regard to the constitution of the red blood corpuscles have undergone considerable change within the last twenty years, different modes of analysis having been employed to separate the organic constituents. This globulins of the older physiologists is now considered as a constituent of hatrnoglobin, which is the proteid substance united with the heematino (see ILEMOGLOBIN). The proteid which is precipitated when a solution of htemoglobln is exposed to the air, though belonging to the globulin family, has characteristics of its own. Preyer call:, it globin. It contains no trace of mineral matter, and therefore, when burned, yields no ash. What are uow called globulins constitute a family. To understand their relations to other proteine bodies, see PROTEMS. These globulins are native proteids which differ from albumins in not being soluble in distilled water, need ing for their solution a minute portion of a neutral salt, such as chloride of sodium (common salt), differing in this latter respect from the albumins, but are like them in not being soluble in distilled water. The globulins are soluble in dilute acids and alka lies, being changed respectively into acid-albumin and alkali-albumin. The globulins are named as follows: 1. Globulin, called also crystallin. If the crystalline the eye is rubbed together with fine white sand, digested with water, and filtered, the filtrate will contain three proteids. If carbonic acid gas is now passed through the clear solution, a copious pre cipitate of globulin, will take place. In its general behavior globulin much resembles Para globulin and fibrinogen. It is readily precipitated on the addition of alcohol. It resembles vitellin in not being precipitated by saturated solution of chloride of sodium.
2. Paraglobulin or .fibrinoplastin. When blood serum is diluted with 10 parts of water, and carbonic acid gas is rapidly passed through it, a flocculent precipitate is formed, which becomes granular, and easily separable by decantation or filtration. It should be washed with water containing carbonic acid to prevent redissolving. A more
complete separation from serum may be effected by saturation with sulphate of magne sia. This yields, according to Hammarsten, about 4.565 parts in 100; but the amount varies in different animals. A characteristic test of paraglobulin is that it produces fibrin when added to many pathological fluids, such as that of the transudations in hydrocele, pericarditis, peritonitis, and pleuritis. Paraglobulin occurs chiefly in blood serum, but is also found in the white corpuscles, in connective tissue, cornea, aqueous humor, lymph, chyle, anti serous fluids.
3. Fibrinogen. This body much resembles paraglobulin in its behavior generally, but the two differ in regard to coagulation by heat. In a weak solution of chloride of sodium, fibrinogen coagulates at from 125° to 131° F., while paraglobulin requires for coagulation a temperature of 154° to 158°. The characteristic test for its presence is the formation of fibrin when its solution is added to a solution of paraglobulin and fibrin-ferment. Fibrinogen occurs in blood, chyle, and various transudations.
4. Myosin. This form of globulin is the chief constituent of dead, rigid muscle. If a dead muscle, from which all fat, tendon, connective tissue, etc., has been removed, is rendered bloodless by a saline injection, and then cut fine and washed with water, when the washing has been continued until no proteid can be detected in the fluid, a large portion of the muscle will remain undissolved; but it will become a viscid mass if treated with a ten per cent solution of chloride of sodium (common salt). If this be placed upon a filter, a filtrate will slowly separate, and if it be allowed to drop in,to large quantity of distilled water, a white flocculent precipitate will result, which is myosin. It is not as soluble as paraglobulin. It coagulates at a temperature of 131° to 140° F. In some of its reactions it resembles fibrin.
5. Trite-11in. This is the chief proteid constituent of the yolk of egg, from which it may be obtained as follows: The yolk is treated with ether repeatedly till no coloring matter is extracted, when the residue is dissolved in a ten per cent solution of chloride of soditnn, and filtered. The filtrate, when added to an excess of water, causes a pre cipitate of vitellin and some other matters, from which it may be separated by alcohol, which coagulates the vitellin. It is a white, granular body, insoluble in water, but very soluble in dilute solution of chloride of sodium, much more so than myosin. It coagu lates between 158° and 17G° F. A saturated solution of chloride of sodium causes no precipitate. In yolk of egg vitellin is always associated with lecethin (q.v.), probably in combination. Before it is freed from this body, vitellin possesses properties consid erably differing from those of the other proteids.