SCIENCE PROGRESS 



IN THE TWENTIETH CENTURY 



A QUARTERLY JOURNAL OF 



SCIENTIFIC WORK 



& THOUGHT 



VOL. VIII 

 NO. 29. JULY 191 3 



EDITOR 



SIR RONALD ROSS, K.C.B., F.R.S., D.Sc, 

 LL.D., M.D., F.R.C.S. 



LONDON 

 JOHN MURRAY, ALBEMARLE STREET, W. 



*9 J 3 



