BIOLOGY IN ITS WIDER ASPECTS 1261 



W'c have, then, the idea that the trajectory of life consists of 

 different arcs which are, to a certain extent, elastic, that can be 

 lengthened out or shortened down for the individual. It is a familiar 

 fact that some people are young till they die. When they die they 

 are old only as regards length of years, which is a very partial measure 

 of life. 



Let us think for a little of each of the arcs of the trajectory. 

 Human life is like a rainbow — there are two slopes — the slope up 

 from ante-natal life to adolescence and the slope down from the 

 waning of mature strength to death. Between them lie various arcs 

 on the crest of the life curve. 



Before Birth. — Robert Chambers, the founder of the great 

 publishing house of W. & R. Chambers, who wrote The Vestiges oj 

 Creation, was a shrewd biologist. In his famous book he gives 

 expression to what seems a sound idea, that the prolonged ante-natal 

 period tends to develop better brains. A long ante-natal period or 

 gestation means a long period of quiescence during which the nerve- 

 cells develop, and it is a very important fact that we never get an 

 extra nerve-cell after we are born. We have nine thousand two hun- 

 dred million nerve-cells in the cortex of our fore-brain, but these are 

 never added to after birth. The whole contingent is, or should be, 

 present at birth. Therefore enormous importance attaches to the 

 quiescent ante-natal chapter during which these nerve-cells are 

 formed. One can understand many things from this point of view: 

 thus an elephant has an ante-natal period of twenty months or more, 

 and a foal of eleven months ; how intelligent are these two animals ! 

 If all the nerve- cells are laid down before birth, the interlinking 

 relations between them coming later, one sees the importance of 

 letting the mother have a quiet time, a time when the developing 

 offspring should not be over-stimulated, a time when some of the 

 maternal hormones are transferred into the offspring. And so 

 we may pass from that hidden chapter, the ante-natal slumber, 

 with emphasis on the fact that it is the time when our whole nervous 

 system is laid down. 



Babyhood. — In the second chapter or arc we have to deal \vith 

 a helpless, fragile, unprepossessing yet extraordinarily fascina- 

 ting young organism. If one has the good fortune to visit a Baby 

 Show, what are the biological impressions that rise in the mind 

 most markedly? The first is an object-lesson in variability. These 

 babies vary : no one baby is like another ; each is itself and no other, 

 each a new individual. The Baby Show is a revelation of the raw 

 materials of evolution, some of them the most precious things in the 

 world. How these new departures should be prized, for who can 

 tell what this or that one may become ? 



Secondly, the biologist reflects that these babies are like so many 

 buds -buds which are still close-packed, but which will be unfolded; 



