ENZYMES OF THE SERUM. 259 



rence of a butyrinase is generally admitted, while the property of this 

 lipase of splitting olein and other neutral fats is not generally acknowledged 

 (ARTHUS, DOYON and MOREL l ). This lipolytic property, if it exists 

 to the extent that HANRIOT ascribes to it, must not be confounded with 

 the transformation of fat into unknown substances soluble in water, a 

 phenomenon first observed by CONNSTEIN and MICHAELIS and further 

 studied by WEIGERT. The occurrence of such a body is positively 

 denied by G. MANSFELD. 2 



Besides the above-mentioned enzymes and thrombin, several other 

 enzymes have been found in the blood-serum, namely, oxidases, catalases, 

 proteolytic enzymes, among which we must mention the polypeptide- 

 splitting enzymes studied by ABDERHALDEN and collaborators, 3 also 

 rennin and several antienzymes. We cannot enter into the discussion 

 of these, nor of the many not chemically characterized bodies which have 

 been called toxines and antitoxines, immune bodies, alexines, hcemolysines, 

 cytotoxines, etc. It is also not within the scope of this book to discuss 

 the precipitines which can be used as a biological reagent on account of 

 their action upon various proteins. It may be sufficient to state that 

 the works of BORDET, EHRLICH, WASSERMANN, SCHUTZE, UnLENHAUT, 4 

 and others have shown that the repeated injection into an animal of a 

 foreign protein body or of blood of a different species of animal so changes 

 the blood of this animal that it acquires precipitating properties toward 

 the injected protein or blood. In this manner we obtain a biological 

 reagent for various proteins and for blood of different animals. This 

 last behavior has become of great forensic importance, due to the work 

 of UHLENHAUT. The various enzymes and antienzymes, toxines and 

 and antitoxines, precipitines, etc., are as a rule precipitated with the 

 globulin, but differ among each other in that some are carried down by 

 the euglobulin, while the others are carried down by the pseudo globulin 

 fraction. 



The non-protein organic constituents of the serum have been especially 

 carefully studied by E. LETSCHE 5 and he has found, besides the previously 

 known bodies, that the serum contains several acids, among which there 

 are two nitrogenous acids whose nature has not been studied. These, 

 including other nitrogenous substances found by him, represent a part 



1 Hanriot, Compt. rend. soc. biol., 48 and 54; Compt. rend., 123 and 132; Arthus, 

 Journ. de Physiol. et de Pathol., 4; Doyon and Morel, Compt. rend. soc. biol., 54; 

 Achard and Clerc, (Lipase in Disease), Compt. rend., 129, and Arch. d. med. expe"r., 14. 



2 Connstein and Michaelis, Pfluger's Arch., 65 and 69; Weigert, ibid., 82; Mansfeld, 

 Centralbl. f. Physiol., 21. 



3 Zeitschr. f . physiol. Chem., 51, 53, 55. 



4 The literature on this subject may be found in bacteriological journals and works. 

 See also L. Michaelis, Biohcem. Centralbl., 3, p. 693. 



5 Zeitschr. f. physiol. Chem., 53. 



