176 



Prof. H. E. Armstrong and Mr. H. W. Gosney. 



compounds iu which the oxygen potential is = that of atmospheric oxygen, 

 and an oxidation place for substances in which it is less than that of 

 atmospheric oxygen. In the absence of some agreement as to the zero point 

 the discussion is likely to be as confused in the future as it has been in the 

 past.] 



BIBLIOGRAPHY. 



Unna, P. G. " Die Reduktionsorte und Sauerstofforte des tierischen Gewebes. Festschr. 



Waldeyer," ' Arch, fur Mikroskop. Anat.,' vol. 78, p. 1 (1911). 

 Unna, P. G. 1 Biochemie der Haut,' Jena, 1913. 



Spiers, F. M. "Contact Electricity," ' Phil. Mag.,' 5th ser., vol. 49, Part 1 (1900). 

 McDonagh, J. E. R., and Wallis, R. L. M. " The Chemistry of the Leucocytozoon 



syphilidis and of the Host's Protecting Cells," ' Biochemical Journal,' vol. 7 



(1913). 



Kite, G. L. "Studies on the Physical Properties of Protoplasm. — I," 'Amer. Journ. 

 Phys.,' vol. 32 (1913). 



Studies on Enzyme Action. XXII. — Lipase (IV) — The Correlation 

 of Synthetic and Hydrolytic Activity. 

 By Henry E, Armstrong, F.R.S., and H. W. Gosney, B.Sc 

 (Received and read April 30, 1914.) 



In the previous communication on this subject, in which the behaviour of 

 Lipase towards^ ethereal salts generally was discussed, it has been argued 

 that the enzyme is specially fitted to determine the hydrolysis of the 

 insoluble, oily, glyceric salts of the higher fatty acids but is not suited to 

 act in aqueous solutions : we expressed the opinion that interaction must be 

 supposed to take place at and between surfaces separated only by a thin 

 film of water at most — in other words, that water in excess is inimical to the 

 occurrence of change. The results we advanced, in conjunction with those 

 deduced from the study of other enzymes, notably urease, also led us to 

 conclude that it is impossible to apply the laws of mass action directly 

 to the interpretation of the changes effected by Lipase. 



Previously we have directed our attention only to the hydrolytic activity 

 of the enzyme : numerous observations are on record which prove that, 

 whether of animal or vegetable origin, it can act reversibly but no com- 

 parative study of the two processes has been made hitherto in the case of fats.* 



* (1) Kastle and Lowenhardt, 'Amer. Chem. Journ.,' vol. 24, p. 491. (2) Hanriot, 

 'Compt. Rend.,' vol. 132, p. 212 (1901). (3) Pottevin, ibid., vol. 136, p. 1152 (1903); 

 (4) ' Bull. Soc. Chim.,' Ill, vol. 35, p. 693 (1906). (5) Dietz, ' Zeit. Physiol. Chem.,' vol. 52, 



