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DIGESTIVE ORGANS AND FOOD 
the same to' water and the acids produced during fermenta¬ 
tion. The dough made from these substitute flours does not 
hold together and is not so distensible as that made from 
wheat flour. These unfavorable conditions of the dough 
can be improved by adding a small amount of what is known 
as the “ proteins of serum/’ a special preparation that is 
in the form of a dry powder. 
336. Adulteration of Foods. — Foods are adulterated either 
by subtracting some of the nutritious parts and substituting 
less valuable parts, or by adding materials which cannot 
act as a food. 
The food formerly subject to the most adulteration was 
milk. This adulteration was accomplished by adding water 
to make the milk go farther when being measured out, and 
adding formalin (for'ma-lin) to make it keep sweet. 
For a time many of the cereals were adulterated with 
sawdust, peanut shucks, or bran. Many of the special 
foods put up in packages used to be adulterated, and it 
would require a long description to enumerate all that have 
been found unsatisfactory for food by the Department of 
Agriculture. 
337. Pure Food Laws. — The Food and Drugs Act passed 
by the United States Congress on June 30, 1906, requires of 
manufacturers of foods and drugs that a definite statement 
be made as to their composition. A number of regulations 
and rules have been issued from time to time. The last 
was issued June 15, 1917, and related to the marking of 
the quantity of food in packages. Here we find that when 
food is in package form, it must be plainly marked in terms 
of weight, measure, or numerical count on the outside of the 
package. The quantity of the contents so marked shall 
be the amount of food in the package. 
This Pure Food and Drugs Act established high standards 
for many of the common and necessary foods of man. Before 
its adoption there was no standard for the manufacturers 
