CATALASE REACTION OF MILK. 321 
when milks were examined under comparable conditions. 
This is shown in the following table. 
Table IT. 
Temperature 25° C. 
Time examined after Concentration of K x 104 Total H.O. 
milking. hydrogen peroxide. decomposed. 
(1) O hrs. 17 min. M/35 29 0-09 
Sere 55 23) 45; a 46 Iai 
Paes 55, LO: 5, Ae 56 1°25 
Peete. | by. ;, M/47 121 0:70 
ey t.. 29 ;, * 21 0-60 
(es, = 40.5 } 42 0-78 
a, 20, ,, M/29 OF 2°42 
The total amounts of hydrogen peroxide decomposed as 
given in the last column, are measured in cubic centimetres 
of the standard hydrogen peroxide solution (1 cc. = °00008 
of a gram of hydrogen peroxide). It appears from a con- 
sideration of the above figures that the activity of the 
enzyme, measured by 4, is not dependent on the stability 
of the enzyme. By stability is meant the power the enzyme 
has of resisting the action of the hydrogen peroxide, and 
this is probably measured by the total hydrogen peroxide 
decomposed. This will again be referred to when the 
action of potassium cyanide on the enzyme is considered. 
The variation in the above figures might be accounted 
for in two ways:—(1) that the catalase is produced by 
bacteria in the milk while in the udder, (2) that varying 
amounts of catalase are secreted, together with the milk, 
by different cows. 
In regard to (1) it has been shown by several workers 
that the milk when first drawn from the udder contains a 
considerable number of bacteria, and, since blood heat is 
U—November 4, 1914. 
