Interesting Paragraph

The paragraph below is very unusual. How quickly can you find out what is so unusual about it?
“Gatsby was walking back from a visit down in Branton Hill’s manufacturing district on a Saturday night. A busy day’s traffic had had its noisy run; and with not many folks in sight, His Honour got along without having to stop to grasp a hand, or talk; for a mayor out of City Hall is a shining mark for any politician. And so, coming to Broadway, a booming bass drum and sounds of singing, told of a small Salvation Army unit carrying on amidst Broadway’s night shopping crowds. Gatsby , walking towards that group, saw a youg girl, back toward him, just finishing a long, soulful oration … ”
The above passage is taken from the book “Gatsby” written by Ernest Vincent Wright in the late 1930’s