CATALASE REACTION OF MILK. 319 
NOTHS on THE CATALASH RHACTION oF MILK. 
By H. B. TAYLOR, B.Sc., 
Science Research Scholar, University of Sydney. 
(Communicated by Professor C. EK. Fawsirt.) 
[Read before the Royal Society of N.S. Wales, October 7, 1914. | 
WHILE investigating some of the physico-chemical con- 
stants of milk’ it was thought desirable to make some 
observations on the catalytic action of milk on certain 
chemical reactions. It is known that milk has the power 
of accelerating the decomposition of hydrogen peroxide and 
it is supposed that this is due to an enzyme, catalase, in the 
milk. Milk is further able to accelerate the rate of action 
of hydrogen peroxide on such substances as hydriodic acid 
and phenylenediamine hydrochloride, and the body causing 
these reactions is similar in many respects to the enzyme- 
peroxydase. The following investigations were undertaken 
in order to examine the catalase reaction more minutely. 
Catalase. 
The action of milk, and an active product obtained from 
it, on hydrogen peroxide were studied. There are various 
methods of following the rate of decomposition of the 
hydrogen peroxide. Two methods have been used here. 
The first, which is suitable for work with milk and hydrogen 
peroxide, consists in taking a definite volume of the mixture 
of milk and hydrogen peroxide at any stage of the reaction 
and running into sulphuric acid which serves to stop all 
action and to precipitate the caseinogen. The quantities 
used in these experiments were :—d cc. of a mixture which 
originally contained 15 cc. of M/10 hydrogen peroxide and 
1 Taylor, this Journal, xiv11, 1913. 
