230 SECRETS OF ANIMAL LIFE 



the offspring, undergoing in a most puzzling way 

 differentiation into nerve and muscle, blood and 

 bone, a residue is kept intact and unspecialized to 

 form the primordium of the reproductive organs of 

 the offspring, whence will be launched in due time 

 another similar vessel on the adventurous voyage 

 of life. So it comes to be that the parent is rather 

 the trustee of the germ-plasm than the producer 

 of the child. In a new sense the child is a chip 

 of the old block. Or, as Bergson puts it in less 

 static metaphor, " life is like a current passing 

 from germ to germ through the medium of a 

 developed organism." Though it is now clear 

 that Weismann exaggerated the contrast and 

 apartness of body-cells and germ-cells, the general 

 idea of the continuity of the germ-plasm remains 

 as one of the most important contributions to post- 

 Darwinian biology. It is the explanation pf the 

 inertia of the main mass of the inheritance, which 

 is carried on with little change from generation to 

 generation. For men do not gather grapes off 

 thorns or figs off thistles. Similar material to 

 start with ; similar conditions in which to develop ; 

 therefore like begets like. 



While the epoch-making experimental work of 

 Mendel, which would have so much delighted 

 Darwin's heart, lay buried in the records of the 

 naturalists' society at Briinn, there was developed 

 in Britain a statistical study of inheritance, especi- 

 ally associated with Sir Francis Galton and Profes- 

 sor Karl Pearson. It was Galton who began to study 



