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 by heat of enzymes in general. 
This table has been compiled from observations recorded by Green 
(62), Oppenheimer (63), and others. 
Name of ferment. 
Temperature at which 
destroyed (°C.). 
j Name of ferment. 
Temperature at which 
destroyed (°C.). 
Bromelin 
AA’^eakened at 70. 
! Maltase 
55. 
Caroubinase 
80, weakened at 70. 
Alyrosin 
81-85. 
Cytase 
60. 
Oenoxydase 
72. 
Dextrinase 
75. 
Papain 
82. 5. 
Diastase (plant) 
80. 
Pepsin 
55-57. 
Diastase (saliva) 
65-70, slowly at 58. 
Rennin 
70, neutral; 63, faintly 
Emulsin 
70. 
acid. 
Enterokinase 
65 (slowly). 
! Trehalase 
64. 
Inv'ertase 
70, very slowly at 45-50. 
j Trvpsin 
75-80. 
Laccase 
60-63. 
Thrombase 
70 (Schmidt). 
Lipase 
72 (Hanriot) , 65-70 
Tvrosina^e 
55. 
(KastleA:Loevenhart). 
1 Urease 
75-80. 
P. T. Midler (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 Aveakened b}^ heating to 66° C. for 
half an hour and at 65°-T0° C. is destroyed. Parachymosin (Bang) 
withstands a temperature of 75° C. for some time. Papain is Aveak- 
ened at 75° C. and destroyed at 82.5° C. The oxidizing ferments 
(Abelous and Biarnes) increase in actiAuty from 0° C. to 60° C. At 
80° C. they are still actAe and are first destroyed at 100° C. Lacto- 
serum (P. T. Muller) is rendered inactiA^e b}" heating for half an 
hour, at 70°-75° C. So far then as the influence of temperature on 
their actiAuty is concerned it is evident that the milk enzymes are 
much like enzymes from other sources. Indeed they are all A^ery 
much alike and all of this great group of substances stand in such 
intimate and close relation to the Autal activities of the cell that all 
of those conditions and influences which tend to destroy the one tend 
also to destroj^ the other. (See also Kastle (65) “ On the Vital 
ActAity 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. 
