100 SCIENCE PROGRESS 



of weight of the bones in old age, are all examples of the 

 organism using these structures for purposes of food, just as 

 the fat and the reserve material in the liver are continually 

 being used for food. In the same way most of the tissues are 

 used to conserve the life of an animal suffering from starvation. 

 On the other hand, examples of apparently useless parts which 

 do not disappear are seen in the human vermiform appendix 

 and in the mammary gland in the male. 



The true position seems to be that the needs of survival 

 will account for large specialised organs, such as the teeth of 

 the baboon. A part not required for survival purposes is dealt 

 with in different ways, and is often tolerated for countless 

 generations. But there has been some force tending towards 

 economy, especially in the hard parts. Since the Eocene this 

 has reduced the size of all bones to the minimum weight con- 

 sistent with due strength. It has modernised the teeth, given 

 the female small bones, and reduced them all in old age. It 

 has converted the inside of the bones into secret laboratories. 

 The brain is conserved at all costs both in development and in 

 times of starvation. The fat is cheap and stored up for hard 

 times. We know that part of this regulation is done by the 

 pituitary and thyroid. It seems that full mental and sexual 

 development cannot be correlated with massive bones, and a 

 very large man has often too weak a heart to carry him through 

 an attack of pneumonia. Hence giants and the Neanderthalers 

 have all died out. This regulating mechanism has only quite 

 recently (that is six thousand years ago) brought forth pro- 

 gressive man in the proto-Egyptians. The apparent atrophy 

 of the Heidelberg jaw and the Talgai palate is not due to 

 disuse, but to the action of these correlating forces, which 

 have in the meantime found the Mediterranean race far more 

 plastic than the Australian aborigine or the Eskimo. 



