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More than 2,500 barbiturates have been synthesized. At the height of their popularity, about 50 were marketed for human use.
The modern decimal position system was the invention of the Hindus (around 800 AD), involving the placing of numerals to indicate their value (units, tens, hundreds, and so on).
Warfarin was developed as a consequence of the study of a strange bleeding disorder that suddenly occurred in cattle on the northern prairies of the United States in the early 1900s.
Asthma-like symptoms were first recorded about 3,500 years ago in Egypt. The first manuscript specifically written about asthma was in the year 1190, describing a condition characterized by sudden breathlessness. The treatments listed in this manuscript include chicken soup, herbs, and sexual abstinence.
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.

