The Rickshaw

My friend John Roderick, a distinguished AP Special Correspondent, recently published a report on Beijing, comparing its present state to that in the late 1940s, when it was known as Peiping. He recalls that in the 40s the rickshaw was almost the only means of public coneyance.
This has led to my research subject for today:

Why no horses ?
I will try to give the answer in tomorrow's posting.