340 
any way responsible for scurvy or rickets, but in reality is a wise 
precaution against infantile diarrhea and other bacterial diseases. 
Similarly Tjaden, Koske, and Hertel (53) claim that by rapidly 
heating the milk to 90° C., with constant shaking, the chemical and 
physical properties of the milk are in no wise altered nor is the value 
of the milk as a food in any way impaired. 
These fundamental differences of opinion regarding the effect of 
heat on the digestibility of milk can therefore only be settled by 
further investigations along this line. 
By way of comparison there are given in the subjoined table cer- 
tain data pertaining to the destruction b} r heat of enzymes in general. 
This table has been compiled from observations recorded by Green 
(62), Oppenheimer (63), and others. 
Name of ferment. 
Bromelin 
Caroubinase 
Cytase 
Dextrinase 
Diastase (plant) . 
Diastase (saliva) 
Emulsin 
Enterokinase . . . 
Invertase 
Laccase 
Lipase 
Temperature at which 
destroyed (°C.). 
Weakened at 70. 
80, weakened at 70. 
60. 
75. 
80. 
65-70, slowly at 58. 
70. 
65 (slowly). 
70, very slowly at 45-50. 
60-63. 
72(Hanriot), 65-70 
(Kastle&Loevenhart). 
Name of ferment. 
Maltase 
Myrosin 
Oenoxydase 
Papain 
Pepsin 
Rennin 
Trehalase . . 
Trypsin 
Thrombase . 
Tyrosinase . 
Urease 
Temperature at which 
destroyed (°C.). 
55. 
81-85. 
72. 
82. 5. 
55-57. 
70, neutral; 63, faintly 
acid. 
64. 
75-80. 
70 (Schmidt). 
55. 
75-80. 
P. T. Muller (64) gives the following data bearing on the subject of 
the resistance of the several ferments to heat: Hemodiastase (Hahn) 
is not destroyed at 55° C. It is weakened by heating to 66° C. for 
half an hour and at 65°-70° C. is destroyed. Parachymosin (Bang) 
withstands a temperature of 75° C. for some time. Papain is weak- 
ened at 75° C. and destroyed at 82.5° C. The oxidizing ferments 
(Abelous and Biarnes) increase in activity from 0° C. to 60° C. At 
80° C. they are still active and are first destroyed at 100° C. Lacto- 
serum (P. T. Muller) is rendered inactive by heating for half an 
hour, at 70°-75° C. So far then as the influence of temperature on 
their activity is concerned it is evident that the milk enzymes are 
much like enzymes from other sources. Indeed they are all very 
much alike and all of this great group of substances stand in such 
intimate and close relation to the vital activities of the cell that all 
of those conditions and influences which tend to destroy the one tend 
also to destroy the other. (See also Kastle (65) “ On the Vital 
Activity of the Enzymes.”) All of the bacteria of milk can not be 
destroyed therefore without at least diminishing the activity of the 
milk enzymes or perhaps destroying them altogether and the enzymes 
can not be destroyed without rendering the milk sterile. 
