FERMENTED MILKS. 7 
Milk is usually looked upon as a nitrogenous food, but it should be 
remembered that it contains about 5 per cent of lactose, a carbohydrate 
which seems to be peculiarly adapted to bacterial fermentation. 
Aside from the possible therapeutic value of fermented milks, there 
can be no question that they are nutritious and refreshing and that 
their use should be encouraged for their food value. 
FOOD VALUE OF FERMENTED MILK. 
The high food value of milk is too generally recognized to need 
discussion here ; fermented milks also have a high food value, except 
that in some cases the fat is partially or entirely removed. Other- 
wise the food value of the fermented milk differs little from that of 
the fresh milk from which it is made. Any increased digestibility 
of the fermented milk is due not so much to change in the chemical 
nature as to the fact that the casein is furnished in a precipitated 
and finely divided condition. In none of the fermented milks is there 
any material cleavage of the casein resembling the digestion in the 
stomach. The fat is practically unchanged, and a part only of the 
sugar is converted into acid, alcohol, or gas. In certain gastric 
troubles in which it is difficult to find any food that can be retained 
by the patient, fermented milks are frequently used with good results. 
Kefir and kumiss especially are used under such circumstances, as 
the stimulating action of the carbon dioxid which they contain is 
believed to aid in their digestion. To the physician the value of a 
highly nutritious food which can be digested when other foods are 
rejected is obvious. 
There are many questions that should be very carefully considered 
before a fermented milk is introduced as an important part of the 
diet. As Herter (41) has pointed out in the admirable paper already 
cited, the addition of fermented milk to the diet may change very 
materially the ratio of protein to other classes of food. If the milk is 
taken in place of other food, the daily protein ration may be so re- 
duced that intestinal putrefaction, which is dependent on the protein 
part of the food, is diminished. On the other hand, if milk is added 
to the usual food, the protein ratio may be increased rather than di- 
minished. In many cases the condition of the mucous membranes 
will not permit the presence of organic acid, and soured milk can not 
be retained. It is also possible that symptoms of autointoxication are 
not caused by unusual bacterial activity in the intestine, but by func- 
tional failure of certain organs. This point could be determined only 
by a physician. It would be very unsafe to consume large quantities 
of milk, fermented or unfermented, under certain pathological con- 
ditions. In any case an important change in the diet should be 
made only upon the advice of a physician. 
