Can't remember where I first came across this. Must have been linked on some cycling blog or other. Anyway, the interesting thing about it from my point of view is the gear ratios mentioned:

it is advised, nevertheless, that he reduces his development to 5 metres or 5m. 20, which is, I assume, 5m. 50 in the summer

I cycle 42:17 in summer which is 5m 30 (with a 32c tyre, but I'm actually on a 30c) and 42:19 in winter which is 4m 80. But I'm not actually doing cyclocross. And offroad I don't really have any hills; some short steep slopes, but not hills. I'm pretty sure anyone doing Cyclocross nowadays wouldn't even do it on a 5m ratio (42:18); Here's another mention of 42:18 as being too high for offroad; I reckon I'd have a go on 42:19, because I happen to have that gearing, but even closer to 2:1 seems to be the done thing.

Obviously cyclocrossers of the 1920's were hardcore.