6 Heredity. 



To the naturalist, on the contrary, the word is filled 

 with deep meaning, and instead of recalling to his mind 

 a few odd cases, the tricks and accidents of heredity, it 

 brings before him the most marvellous of all the phe- 

 nomena of the material universe: the production from a 

 simple egg of a living animal, with the intricate struc- 

 ture and complex bodily and mental functions of its 

 proper species. 



Thoughtful men of all ages have regarded the struc- 

 ture and faculties of the higher animals as a proper field 

 for life-long study. Yet the acute intellects, the powers 

 of patient observation and profound reflection which 

 generations of naturalists have brought to this fascinat- 

 ing subject, have not yet given us a complete knowledge 

 of the life of a single animal. 



In every age and country where science has flourished 

 men have devoted their lives to this subject, and have 

 felt that their hardly-earned results could scarcely be 

 called a beginning. So vast is the field, so many are 

 the phenomena, that the province of natural science is 

 practically infinite, for each animal and each plant pre- 

 sents special problems which open out in all directions 

 before the student in an endless vista. 

 . Wonderful and various as the attributes of each ani- 

 mal are, however, they are not mysterious; for, at the 

 same time that we discover in an organism the power to 

 do wonderful things, we also find in it a material organi- 

 zation, a mechanism, adopted to do these very things. 

 It is true that we cannot perfectly understand this mech- 

 anism, that in many cases we fail completely in our 

 attempts to trace its working, and that in most cases our 

 insight is very crude indeed. Still we are able to show 

 that the machinery exists; and anatomy, or the study of 

 structure, goes hand in hand with the study of the bodily 



