Ball, — On the Action of Pectase. 357 



Summary. 



1. During the action of pectase on a solution of pectin the electrical 

 conductivity of the mixture remains practically constant, showing tliat a gel 

 is formed, and not merely a very viscous liquid. 



2. The changes in viscosity during coagulation were determined by means 

 of a viscosimeter of the Ostwald type. By comparison of experiments at 

 C. and 14° 0. the activity of the enzyme was found to be very muoli 

 greater at the higher temperature. 



3. Tlie viscosity was found to increase slowly at first, then more rapidly 

 until a maximum was reached, and this was followed by a rapid decrease. 

 Increase in the amount of electrolytes present lowered the maximum, while 

 a decrease in tlie electrolytes raised it. The decrease in viscosity is probably 

 to be explained by the action of the electrolytes in clumping together the 

 particles of colloid forming the reticulum of the gel, so that a suspension is 

 produced. 



I am indebted to Dr. W. R. G. Atkins, both for having originally 

 suggested the nature and methods of this research, and for many valuable 

 suggestions while tlie work was in progress. 



I am also indebted to Professor H. H. Dixon for the benefit of his 

 advice on many portions of this work. 



Bibliography. 



(1) Bertrand et Mallevre. — Sur la pectase et sur la fermentation pectique. 



Compt. Rend., 1894, cxix, 1012. 

 (2) Nouvelles recherches sur la pectase et sur la fermentation 



pectique. Compt. Rend., 1895, cxx, 110. 

 (3) Sur la diffusion de la pectase dans le regno vegetal et sur 



la preparation de cette diastase. Compt. Rend., 1895, cxxi, 726. 



(4) BouRQUELOT. — Sur les pectines. Journ. de Pliarm. et de Chim., 1899, 



ix, 563. 



(5) BouRQUELOT et H£rissey. — De Taction des ferments solubles sur les 



produits pectiques de la racine de gentiane. Journ. de Pharm. et de 

 Chim., 1898, viii, 145. 



(6) Sur la pectiue de Cynorrhodon. Journ. de Pharm. et de 



Cliim., 1899, x, 5. 



(7) Browne, C. A. — Handbook of Sugar Analysis. New York (John 



Wiley & Sons), 1912. 



(8) EuLEK, H. — General Chemistry of the Enzymes. English Translation 



by T. H. Pope, New York (John Wiley & Sons), 1912. 



(9) FrEmy. — Recherclies sur la pecline et I'acide pectique. Journ. de Pharm., 



1840, xxvi, 368. 



SCIENT. PEOC. K.D.S., VOL. XIV, NO. XXVIII. 8 M 



