738 APPENDIX. 



(c) Paraglobulin. Paraglobulin is contained in serum and in 

 serous and synovial fluids, and may be precipitated by saturating serum 

 with solid sodium chloride or magnesium sulphate, as a bulky flocculent 

 substance, which can be removed by filtration after standing for some 

 time. 



It may also be prepared by diluting blood serum with ten volumes of 

 water, and passing carbonic acid gas rapidly through it. The fine pre- 

 cipitate may be collected on filter, and washed with water containing 

 carbonic acid gas. 



It is very soluble in dilute saline solutions, from which it is precipi- 

 tated by carbonic acid gas or by dilute acids; its solution is coagulated 

 at 70 C. ; even dilute acids and alkalies convert it into acid- or alkali- 

 albumin. 



(D) Fibrinogen. Fibrinogen is prepared from hydrocele fluid or 

 other serous transudation by methods similar to those employed in pre- 

 paring paraglobulin from serum. 



Its general reactions are similar to those of paraglobulin; its solution 

 is coagulated at 52-55 C. Its characteristic property is that, under 

 certain conditions, it forms fibrin. 



(E) Vitellin. Vitellin is prepared from yolk of egg by washing 

 with ether until all the yellow matter has been removed. The residue 

 is dissolved in 10 per cent saline solution, filtered, and poured into a 

 large quantity of distilled water. The precipitate which falls is impure 

 vitellin. 



It gives the same tests as myosin, but is not precipitated on saturation 

 with sodium chloride; it coagulates between 70 and 83 C. 



(F) Globin. Is the proteid residue of haemoglobin. 



CLASS IV. 



Fibrin. Fibrin can be obtained as a soft, white, fibrous, and very 

 elastic substance by whipping blood with a bundle of twigs, and washing 

 the adhering mass in a stream of water until all the blood-coloring mat- 

 ter is removed. 



Tests. It differs from all other proteids, in having a filamentous 

 structure. It is insoluble in water and in dilute saline solutions; slightly 

 soluble in concentrated saline solutions, soluble on boiling in strong acids 

 and alkalies. On boiling it is converted into coagulated proteid. When 

 dissolved in strong saline solution it gives many of the same reactions as 

 myosin. When dissolved in acids or alkalies, it is converted into the 

 corresponding derived-albumin. It gives a blue color with tincture of 

 guaiacum and ozonic ether. 



