ANATOMY 



almost beyond the limits of human conception. 

 The organisation of the vast armies engaged in the 

 Titanic struggle of the Great War was but a feeble 

 and incompetent effort by comparison. 



What are the directing influences responsible 

 for this infinitely complex organisation is a ques- 

 tion which naturally suggests itself. The first 

 answer to such a question must be hereditary 

 influence. We have learnt from our forebears ; 

 the building cells of the body have been schooled 

 through countless generations. This may be an 

 answer, perhaps, but it is not an explanation, and 

 we are looking to the student of Genetics to 

 discover how the factors influencing form are 

 transmitted from parent to offspring. 



The stresses to which the skeleton is subject 

 during the lifetime of the individual contribute 

 another influence which determines to some extent 

 the work of the bone-builders. We know this for 

 a certainty. During its building the thigh-bone 

 undergoes not only an increase in bulk, but also 

 a change in form. Although the form-changes 

 are not excessive, they are easily identified. If it 

 were possible to magnify the thigh-bone of an 

 infant and make it of a size corresponding to the 

 thigh-bone of an adult, the one could be dis- 

 tinguished from the other at a glance. That these 

 changes are a reaction, to some extent at all events, 

 to the pressure and pulls to which the skeleton is 



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