692 BACTERIOLOGY OF MILK 
should be employed to educate mothers and those caring for infants, 
in proper methods. This, it is believed, can most effectively be done 
by the visits of properly qualified trained nurses or women physicians 
to the homes, supplemented by the use of printed directions. 
"11. Bad surroundings, though contributing to bad results in feeding, 
are not the chief factors. It is not, therefore, merely by better housing 
of the poor in large cities that we will see a great reduction in infant 
mortality. 
"12. While it is true that even in tenements the results with the best 
bottle feeding are nearly as good as average breast feeding, it is also 
true that most of the bottle feeding is at present very badly done; 
so that, as a rule, the immense superiority of breast feeding obtains. 
This should, therefore, be encouraged by every means and not dis- 
continued without good and sufficient reasons. The time and money 
required for artificial feeding, if expended by the tenement mother to 
secure better food and more rest for herself, would often enable her 
to continue nursing with adA-antage to her child. 
"13. The injurious effects of table food to infants under a year old, 
and of fruits to all infants and young children in cities, in hot weather, 
should be much more generally appreciated." 
These observations do not correlate the incidence of diarrhea with 
specific microorganisms, but they do furnish strong presumptive 
evidence of the relative salubrity of milk containing small numbers 
of bacteria. The importance of a consistently low bacterial content 
in milk designed for human consumption has been generally recog- 
nized by city, state and national health bureaus, and the grading and 
control of public milk supplies has been one of the great hygienic 
questions of the last decade. The older conception of a chemical 
standard to safeguard the financial interest of the consumer has been 
broadened to include a bacteriological standard which aims to exclude 
milk containing an excessive number of bacteria from the public 
market. The bacterial standard adopted varies somewhat in different 
cities, but in general it is so defined that all milk which meets its 
requirements must of necessity be produced in clean dairies, handled 
carefully and consistently maintained at a low temperature. The 
bacterial standard is based upon the number of bacteria per cubic 
centimeter of milk and it is rapidly becoming a custom to recognize 
grades of milk, each of which must conform to certain regulations 
regarding production, handling and bacterial count. 
Certified milk is the hygienic grade milk. It is usually the product 
of a single dairy; the cows must be free from tuberculosis or other 
disease and stringent regulations for the condition of the entire plant 
are laid down. The milk as delivered must contain less than the 
maximum number of bacteria per cubic centimeter, as set forth in 
the standard. Usually the standard specifies 10,000 to 30,000 bacteria 
per cubic centimeter. Certifiefl milk is usually safe milk, but con- 
tamination of it with human pathogenic organisms is not at all im- 
