158 ESSENTIALS OF CHEMICAL PHYSIOLOGY 



chloride is added, but not if the oxalate plasma has been previously heated to 

 60° C. and filtered, because the fibrinogen has been thus removed. 



4. Hydrocele Fluid. — This does not clot spontaneously, or only very slowly- 

 Divide it into four parts — A, B, C, and D. 



To A add an equal volume of serum. 



To B add a few drops of fibrin-ferment solution. 



To C add a piece of buffy coat. 



Put them into the warm bath, and coagulation takes place in each. The 

 serum or the buffy coat supplies the missing fibrin ferment. The serum 

 does not produce its effect in virtue of the serum globulin it contains ; 

 hydrocele fluid contains both fibrinogen and serum globulin, as the following 

 experiment shows : — 



Take the portion D and half saturate it with sodium chloride by adding 

 to it an equal bulk of saturated solution of sodium chloride. Fibrinogen is 

 precipitated. The precipitate is a small one, and on standing aggregates 

 together, and so becomes more apparent. Filter, and satiirate the filtrate 

 with sodium chloride, or, better, magnesium sulphate ; serum globulin is 

 precipitated. 



5. Intravascular coagulation. — A solution of nucleo-proteid from the 

 thymus, testis, lymphatic glands, or kidney has been prepared beforehand by 

 the demonstrator. It may be prepared in one of two ways. 



(a) Wooldridge's Method. — The gland is cut up small and extracted with 

 water for twenty-four hours. Weak acetic acid (0'5 c.c. of the acetic acid of 

 the ' Pharmacopoeia ' diluted with twice its volume of water for every 100 c.c. 

 of extract) is then added to the decanted liquid. After some hours the pre- 

 cipitated nucleo-proteid (called tissue -fibrinogen by Wooldridge) falls to the 

 bottom of the vessel. This is collected and dissolved in 1-per-cent. sodium 

 carbonate solution. 



(6) The Sodium Chloride Method. — The finely divided gland is ground 

 up in a mortar with about an equal volume of sodium chloride. The re- 

 sulting viscous mass is poured into excess of distilled water. The nucleo- 

 proteid rises to the surface of the water, where it may be collected and 

 dissolved as before. 



A rabbit is anaesthetised, and a cannula inserted into the external jugular 

 vein. The solution is injected into the circulation through this. The 

 animal soon dies from cessation of respiration ; the eyeballs protrude and 

 the pupils are widely dilated. On opening the animal the heart will be found 

 still beating, and its cavities (especially on the right side) distended with 

 clotted blood. The vessels, especially the veins, also are full of clot. 



