CHEMISTRY OF THE LIVER. 313 



Bactericidal Products. It is worthy of note that in these 

 autolytic decompositions substances are formed which have a 

 marked bactericidal action. This has been shown in many 

 ways and the suggestion appears reasonable that in the con- 

 tinuous breaking down processes going on in various organs 

 we have some of the factors of natural immunity. These 

 autolytic products must not be confounded with the alexins 

 already referred to. In a few experiments on record injec- 

 tions with pressed out juice from autolyzed organs have been 

 sufficient to prevent death in small animals infected with viru- 

 lent cultures. The bactericidal action of the fresh liver or 

 other organ is comparatively slight. 



OTHER FERMENT ACTIONS. 



Other ferments present in the liver have not been very 

 thoroughly studied. The presence of a fat-splitting ferment 

 or lipase has been shown, but little is known of the extent of 

 its action in the body. The oxidase ferments are better 

 known and the action of liver extracts in bringing about oxi- 

 dations of various organic substances has been studied with 

 the object of throwing some light on normal oxidations in the 

 body. How many of these oxidizing ferments the liver may 

 contain is of course not known. The reaction thus far the 

 most carefully studied is that between water extracts of the 

 liver and salicylic aldehyde. In the process this becomes sali- 

 cylic acid. 



The action of a liquid obtained by pressing the minced liver 

 ground up with sand has been studied with reference to its 

 power of hydrolyzing certain esters. Amyl salicylate seems 

 to be readily split by this liver juice. The reaction points to 

 the presence of a lipase-like ferment which doubtless has the 

 power of splitting other bodies of this type. The boiled liquid 

 is without the ester-splitting power. It has been found fur- 

 ther that the active element can be completely salted out by 

 addition of ammonium sulphate to saturation, and it may be 

 precipitated by addition of a strong solution of uranium 

 acetate. 



