Paris is a city of centralisation--and centralisation and classification are closely allied. In the early times, when centralisation is becoming a fact, its forerunner is classification. All things which are similar or analogous become grouped together, and from the grouping of groups rises one whole or central point. We see radiating many long arms with innumerable tentaculae, and in the centre rises a gigantic head with a comprehensive brain and keen eyes to look on every side and ears sensitive to hear--and a voracious mouth to swallow.