SPECIAL TOXICOLOGICAL TESTS 273 



are however absorbed quite slowly which makes it possible for per- 

 sons in good health to take comparatively large quantities of weak 

 solutions without producing serious harm. They are protoplas- 

 mic poisons and it is due to this property that they hemolyze blood 

 causing it to become laky. It has been demonstrated experimen- 

 tally that saponins act more energetically upon blood corpuscles 

 separated from the serum because the serum contains cholesterin 

 which retards hemolysis. It is suggested that the hemolytic 

 action of saponins is due to the removal of the lining membrane 

 of the corpuscles which consists of lecithin, forming lecithin-sa- 

 ponin. Saponins also combine with cholesterin (forming choles- 

 terin-saponin) and the affinities of any saponin being satisfied 

 by the cholesterin, it no longer acts upon the lecithin. This ex- 

 plains why cholesterin retards or checks the hemolytic action of the 

 saponins. The saponins also dissolve white blood corpuscles but 

 to a much weaker degree. 



In making the blood tests for the presence of saponins, isotonic 

 (to blood serum) or physiological salt solution (0.9 per cent.) is 

 added to the defibrinated blood, 100 parts to one of the defibrin- 

 ated blood. Dilute the suspected saponin bearing substance with 

 physiological salt solution and add it to the diluted blood suspen- 

 sion. If saponin is present the mixture at once becomes laky due 

 to hemolysis. Githagin will develop the hemolytic action in 

 dilutions of i : 50,000. 



It must be borne in mind that a variety of substances will pro- 

 duce hemolysis, such as ether, chloroform, alkalies, gallic acid and 

 solanine. The lytic test above outlined may be employed as a 

 check or corroboration of the chemical and perhaps additional 

 biological tests. 



Chemical Hemolysis. — Vandevelde has suggested a method for 

 determining the toxicity of chemical compounds by hemolysis. 

 Defibrinated ox blood is used in addition to the following solutions. 

 A solution of 0.9 per cent, of salt in 50 per cent, alcohol (by volume, 

 specific gravity of 0.9548 at 15° C); physiological salt solution 



