NITEOGENOUS OEGANIC CELL-CONSTITUENTS. 97 



precipitated by alcohol and by carbonic acid, and by the addition of a 

 large quantity of water to their solutions ; sodium chloride added in 

 bulk to their solutions, as a rule, precipitates them. 



Five different kinds of globulins have been recognized. 



1. Vitellin. — Vitellin is found in the yelk of eggs and in the crys- 

 talline lens. It may be prepared by shaking the yelks of eggs with 

 separate portions of ether until all the yellow color is removed, dissolv- 

 ing the residue in dilute sodium chloride solution, filtering and precipi- 

 tating the filtrate with excess of water. So obtained, it always contains 

 lecithin. It is not precipitated by the addition of sodium chloride in 

 substance to its solutions. It is soluble in dilute acids, and is readily 

 converted into syntonin, and by neutralization and re-solution with 

 alkalies into alkali albuminate. Its point of coagulation ranges from 

 t0° to 80° C. It is also coagulable by alcohol. 



2. Myosin. — Myosin is formed in the rigor mortis of muscles, and 

 probably also in the gradual death of all forms of protoplasm. It is 

 precipitated from its solutions in dilute sodium chloride by the addition 

 of common salt in excess. It is also precipitated from its solutions by 

 excessive dilution with water. Its general properties will be more closely 

 considered under the chemistry of muscles. 



3. Paraglobulin. — This substance will be described under the con- 

 sideration of the coagulation of the blood. Hammarsten states that a 

 very much larger quantity of this body is found in the blood of domestic 

 animals than has been heretofore supposed. According to him, more 

 than half of all the albuminoids in the blood consists of paraglobulin. 



i. Fibrinogen. — This is also a globulin found in the blood, and its 

 consideration will likewise, for the present, be deferred. 



5. Globulin, or Crystallin, is contained in the crystalline lens, and 

 it resembles vitellin in that it is not precipitated from its solutions by 

 saturation with sodium chloride, but it is readily precipitated by alcohol. 



Representatives of the group of globulins are also found in the vege- 

 table kingdom. According to Dr. Sidney Martin, vegetable globulins 

 may be divided into two classes, namely, vegetable myosins and vege- 

 table paraglobulin s. The myosins, obtained from the flour of wheat, 

 rye, and barley, have similar properties ; they are all readily soluble in 

 10 to 15 per cent, sodium chloride solution, and are precipitable from this 

 solution bj- saturation with sodium chloride or magnesium sulphate. 

 They are soluble in 10 per cent, magnesium sulphate solution, and are 

 coagulated in this solution at a temperature of 55° to 60°. If the salt is 

 dialyzed away from the saline solution of myosins, the latter is precipi- 

 tated ; but the precipitate is no longer a globulin, since it is insoluble in 

 saline solutions. It is soluble in dilute acids and alkalies (0.2 per cent.) ; 

 it is precipitable from these solutions by neutralization, the precipitate 



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