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In 1864, the first barbiturate (barbituric acid) was synthesized.
When blood is deoxygenated and flowing back to the heart through the veins, it is dark reddish-blue in color. Blood in the arteries that is oxygenated and flowing out to the body is bright red. Whereas arterial blood comes out in spurts, venous blood flows.
As the western states of America were settled, pioneers often had to drink rancid water from ponds and other sources. This often resulted in chronic diarrhea, causing many cases of dehydration and death that could have been avoided if clean water had been available.
In 1844, Charles Goodyear obtained the first patent for a rubber condom.
Cancer has been around as long as humankind, but only in the second half of the twentieth century did the number of cancer cases explode.