Vlll PREFACE 



man wholly untinged by the ambitions of wealth and power, 

 once remarked to me that there were no people so difficult to 

 instruct as those who were ignorant of their own ignorance. 

 It is just these very persons who, when placed in high positions 

 of social, political, or professional trust, most powerfully con- 

 tribute to check a nation's progress. There are too few 

 genuine workers at science in this country. As one of the 

 rank and file, I claim only to have honestly contributed my 

 mite. I should like to see a small army of helminthologists 

 rise up and lay siege to the fortresses at present securely held 

 by thousands of death-dealing parasites. 



T. S. C. 



74, PORTSDOWN ROAD, LONDON 

 May, 1879. 



