FAT-SPLITTING TISSUE FERMENTS 405 



by no means, to the writer's way of thinking, satisfactorily 

 removed from the plane of uncertainty. 



Fat-splitting Tissue Ferments. This feeling of uncer- 

 tainty grows when we come to consider the true lipases, that 

 is, those tissue ferments which bring about cleavage of neu- 

 tral fats into their components. There are a few references 

 in literature to this type of ferments. 13 P. Saxl, 14 in follow- 

 ing these up in control tests, obtained results indicating that 

 neutral fat, both that contained in the tissues and that added 

 thereto undergoes but a slight degree of cleavage during 

 postmortem autolysis (excluding action of bacteria). The 

 author's usual contention, however, here applied to Saxl's 

 negative findings, would rank them as of less relative value 

 than the positive results of other authors, who, like Umber 

 and Brugsch, 15 Pagenstecher 16 , and Berczeller, 17 conducted 

 their experiments carefully and added the fat in the form 

 of an emulsion to the tissue pulp. In experiments of this 

 sort it is likely, too, that activation of zymogens plays an 

 important role. Thus in the adipose tissue of freshly killed 

 hens practically no lypolytic power can be detected; but it 

 appears after they are kept for a long time. 18 It is im- 

 possible here to enter in detail into the ferment-kinetics of 

 the lipases ; only a few more features seemingly essential to 

 a sketch of their characteristics, may be briefly mentioned. 



13 Ludy; Ramond (1889), 1904; N. Sieber, Zeitschr. f. physiol. Chemie., 55, 

 177, 1908. 



"P. Saxl, 1. c.; cf. also G. Comessati, Clin. Med. Ital., 46, 417, cited in 

 Jahresber. f. Tierchem., 38, 179, 1908. 



15 F. Umber and Th. Brugsch, Arch. f. exper. Pathol., 55, 164, 1906. 



16 A. Pagenstecher (Heidelberg), Biochem. Zeitschr., 18, 285, 1908; cf. also 

 A. Juschtschenko (St. Petersburg), Biochem. Zeitschr., 25, 49, 1910; G. Izar 

 (Catania), ibid., 40, 390, 1912. 



17 L. Berczeller (F. Tangl's Lab., Budapesth), Biochem. Zeitschr., 44, 185, 

 1912. 



18 M. E. Pennington and J. S. Hepburn, Jour. Amer. Chem. Soc., 84, 210, 

 1912; United States Dept. of Agriculture, Bureau of Chem., Circular No. 75, 

 1911, cited in Centralbl. f. d. ges. Biol., 13, No. 5, and 156, 1912. 



