404 FAT-SPLITTING TISSUE FERMENTS 



tried out these statements at the request of the author, found 

 that the first three esters above named are split in only very 

 slight but always measurable degree by short exposure (an 

 hour at room temperature) to the influence of minced tissues 

 (but salicylic acid amylester was split by almost all the tis- 

 sues studied). On longer exposure to the same influence 

 usually a marked access of acidity could be recognized titri- 

 metrically, brought about not only by the cleavage of the 

 esters but also by formation of acid by autolysis of the tis- 

 sues. Saxl came to the conclusion that none of the recom- 

 mended methods is adapted to quantitative study of ester 

 cleavage, and that all the statements dealing with quantita- 

 tive variations of lipase in the tissues are without proper 

 foundation. 9 P. Rona has shown that tracing the change in 

 surface tension of a solution of monobutyrin or tributyrin 

 may also be employed in the recognition of ester-splitting 

 ferments in aqueous extracts of tissues. 10 But this method 

 has not been properly elaborated as a quantitative one any 

 more than the rest. The greatest problem in this connec- 

 tion not as yet solved, and perhaps not capable of solution, 

 is that of quantitative extraction of the lipases from a tissue. 

 Studies upon animal and plant lipases especially have raised 

 reasonable doubt as to whether the lipases are at all 

 soluble in water and whether they are separable from organ- 

 ized cytoplasm. 11 With this should be associated the strik- 

 ing observation that the ester-splitting power of freshly 

 prepared tissue extracts becomes enormously augmented 

 when they are preserved on ice. 12 All in all, this matter is 



B P. Saxl (under direction of 0. v. Fiirth), Biochem. Zeitschr., 12, 343, 

 1908; consult therein the older Literature: Hanriot, P, Th. Mtiller, Kastle and 

 Loevenhart, R. Magnus, N. Sieber; cf. also L. B. Mendel and Leavenworth, 

 Amer. Jour, of Physiol., 21, 95, 1908. 



10 P. Rona, Biochem. Zeitschr., 32, 482, 1911. 



"Astrid and Euler, Hoyer, Armstrong, Nicloux, cited in H. M. Vernon, 

 1. c., p. 60; L. Breczeller (Tangl's Lab.), Biochem. Zeitschr., 34, 170, 1911. 



12 M. C. Winternitz and R. Meloy (Johns Hopkins Univ.), Jour. Med. 

 Research, 22, 107, 1910. 



