STUDIES OF MARKET MILK. 165 
at a price much in advance of that asked for the ordinary milk. 
Milk produced under these conditions is sold under various 
names, such as ‘‘certified milk,’’ ‘‘sanitary milk,’’ and ‘‘clin- 
ical milk.’?’ Such milk is commonly recommended by phy- 
sicians who from time to time inspect the farms where it is 
produced and test the milk for its germ content. Such milk 
commonly sells for a price so much higher than the ordinary 
milk that most people feel that they cannot afford to use it 
except where recommended by physicians for specific cases for 
the use of invalids or for infants. At the present time most of 
our states and cities have fairly satisfactory laws in regard to 
the chemical composition of milk sold within their territories 
and these laws are fairly well enforced by the health boards 
and milk inspectors. This insures to the consumer a reason- 
ably good quality of milk so far as its chemical composition is 
concerned and the consumer need have but little fear of getting 
milk which does not come up to the local requirements so far 
as fat and total solids are concerned. These same local author- 
ities also very carefully guard the consumer against the use of 
chemical preservatives in market milk within their jurisdiction. 
There may be, and frequently is, but little difference so far as 
chemical composition is concerned between the ordinary milk 
supply and that sold under the name of ‘‘sanitary’’ or ‘‘cer- 
tified’’ milk. Both may be rich in milk fat and in solids and 
be free from any chemical preservatives, yet one may be a per- 
fectly wholesome food while the other is decidedly unwhole- 
some if not positively poisonous. The principal difference 
between these two grades lies in the sanitary conditions under 
which the milk has been produced and handled. 
Bacteria content of market milk.—With the development of 
the science of bacteriology it has become possible to study the 
sanitary condition of the milk which is being daily consumed 
as human food. The health boards and other authorities are 
at present making a determined effort to ascertain the real. 
condition of the milk which is delivered in our larger cities 
and in many instances the conditions brought to light by these 
examinations are appalling. Park* in New York found that 
“during the coldest winter weather the milk in New York 

* The Bacterial Content of City Milk. H.W. Park, Science, Vol. 13, 1901, p. 322. 
