What was the state of American medicine in the late 19th and early 20th centuries?Please include the specific problems caused by the lack of...

American medical technology was still pretty limited in
the late 19th and early 20th centuries.  There were also relatively few factories that
generated pharmacy drugs, and almost no rules on how safe they had to be for the public
to use.

In some old movies you see characters
selling remedies and elixirs out of their wagons or suitcases as the magical stuff that
cured anything from bellyaches to cancer.  Of course, they almost never worked and were
usually full of stuff that actually hurt you.  So the country had a shortage of reliable
medicine. (Side Note:  The Bayer Aspirin Company, one of the first big
drugmakers, invented heroin as a pain reliever in the 1890s and it was legal to sell. 
Unfortunately, of course, there were serious side effects)  Most vaccines had
not yet been developed by this time, and so our population was continually vulnerable to
epidemics, particularly measles, influenza and yellow
fever.

Much of the rest of the country was underdeveloped,
without much access to the large cities outside of a railroad, and almost no factories
in the west at all.  So often it was either too expensive or too difficult to get
medical supplies to small town America.

Medical technology
in terms of instruments for surgery and dental work were very primitive, and today we
would scream if we saw those instruments when we went to the
doctor.