THE ANIMATE WORLD A UNITY. 533 



follow the development of an individual through its different 

 ages, we follow the development of the animate world through 

 the phases of its existence that we call the geological ages. 



When an old man feels the weight of years, he realizes indeed 

 that his youth has departed from him ; but at what moment did 

 he pass from infancy to youth, and then to maturity and old age ? 

 He does not know ; the phases of his life have unfolded them- 

 selves gradually. Things have gone in the same way for all 

 beings. The world has not to-day the physiognomy it once had, 

 but no one can say in what instant it passed from its Primary 

 condition to its Secondary, and from that to its Tertiary, and then 

 to its Quaternary and present. The change of beings has been 

 slow and gradual. 



The development of man that is, of the individual himself 

 in which the marvels of the animate world are summarized, pre- 

 sents the following phases : 1. Multiplication of constituent parts 

 that is, numerous points of ossification appear which will be- 

 come separate bones. 2. Differentiation of parts. As the parts 

 multiply, they differentiate themselves ; thus points of ossifica- 

 tion similar in the beginning take on differences as they proceed ; 

 one becomes the humerus, another the radius, another the orbital 

 bone, etc. 3. Growth of parts. At the same time that they mul- 

 tiply and differentiate themselves they are growing. 4. Progress 

 of activity. Besides material progress, there is progress of a high- 

 er order from the passive existence within his mother's womb 

 till the individual reaches active life and manifests an energy of 

 his own. 5. Progress of sensibility. Sensibility increases at the 

 same time with activity, and sometimes determines it. 6. Prog- 

 ress of intelligence. Finally, intelligence appears. Last come, it 

 also goes away last with sensibility, and will console the old man 

 in the enfeeblement of his other faculties. 



The history of the animate world, considered in the aggregate 

 of geological times, is very similar to the history of a man in 

 his brief life. We may study in succession the multiplication of 

 beings on the surface of the globe ; their differentiation ; their 

 growth ; the progress of activity; the progress of sensibility ; and 

 the progress of intelligence. Translated for the Popular Science 

 Monthly from the Revue des Deux Mondes. 



The report of the British Association's committee on seismological ob- 

 servations recommends that, since it has been proved that any important 

 earthquake is felt all over the globe, ari'angements should be inade for the 

 record and study of these movements. Such records might prove as impor- 

 tant as those of, for instance, terrestrial magnetism ; and just as we have 

 magnetic observatories in all parts of the world, so should there be seismo- 

 logical observatories. 



