viii Illustrations 



PACING 

 PACK 



DIAGRAMMATIC CROSS-SECTION THROUGH THE RETINA OR PERCIPIENT 



LAYER AT THE BACK OF THE EYE (AFTER HESSE) .... 347 



REPRESENTATION OF A VERTICAL CUT THROUGH THE EYEBALL IN ITS 



SOCKET ... 350 



From The Household Physician, by permission of Blackie & Son, Ltd. 



SECTION OF HUMAN SKIN ......... 350 



Reproduced by courtesy of Messrs. F. Davidson & Co. 



DIAGRAMS SHOWING THE SITUATION OF THE IMAGE IN A NORMAL EYE, 

 IN THE MYOPIC OR SHORT-SIGHTED EYE, AND IN THE HYPERMETROPIC 

 OR LONG-SIGHTED EYE . . . . . . . . .351 



STATUE SHOWING HUMAN MUSCLES . .... 354 



Photo: Anderson. 



DIAGRAM OF THE HUMAN EAR (AFTER HESSE AND WEBER) . . . 355 



PROFESSOR E. H. STARLING ......... 358 



Photo: Elliott & Fry, Ltd. 



PROFESSOR W. M. BAYLISS . . . . . . . . 358 



Photo: Russell, London. 



SIR JAMES YOUNG SIMPSON (1811-1870) ...... 359 



Photo: Rischgitz Collection. 



LORD LISTER .......... 359 



Photo: Rischgitz Collection. 



PROFESSOR WILLIAM BATESON, F.R.S. ....... 368 



Photo: Becker and Maas. 



GREGOR MENDEL, ONE OF THE FOUNDERS OF THE SCIENTIFIC STUDY OF 



HEREDITY 368 



Photo: Rischgitz Collection. 



A RAT-BREEDER'S TRIUMPH ......... 369 



VARIATION IN THE MAGPIE MOTH ....... 369 



A FACTOR IN THE STRUGGLE FOR EXISTENCE (PEREGRINE FALCON 



ATTACKING A ROOK) (Coloured Illustration) .... 372 



Reproduced by courtesy of Messrs. Methuen & Co. from A History of 

 Birds, by W. P. Pycraft. (After a drawing by G. E. Lodge.) 



JAPANESE LONG- TAILED FOWL OR TOSA FOWL ..... 376 



COMBS OF FOWLS ........... 377 



HEREDITY IN WILLOWS (AFTER WIESNER) 380 



